feat: recent searches history in SearchScreen (U3)

Store last 10 search queries in a new search_history_entries DB table
(schema v27). Show them as chips below the search field when it is
focused and empty; tapping a chip re-runs the search. Add a "Clear"
button to wipe all history.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

PLAN_ISSUE_21.md

@@ -0,0 +1,59 @@
+# Implementation Plan: Secure WebView for HTML Emails (#21)
+
+## Goal
+Replace the current `flutter_html` based rendering with a hardened WebView-based approach to improve rendering fidelity while strictly enforcing security and privacy.
+
+## 1. Dependency Management
+- **Core**: `webview_flutter` (v4+)
+- **Linux Platform**: `webview_flutter_linux` (Official community-supported or WebKitGTK based implementation). *Note: I will verify the exact package name during implementation.*
+- **Utilities**: `url_launcher` (existing) for opening links in the system browser.
+
+## 2. Secure WebView Component (`lib/ui/widgets/secure_email_webview.dart`)
+Create a new widget `SecureEmailWebView` that encapsulates the `WebViewWidget` and its controller.
+
+### Configuration & Hardening
+- **Disable JavaScript**: `controller.setJavaScriptMode(JavaScriptMode.disabled)`.
+- **Background**: Match the application theme (e.g., transparent or surface color).
+- **Security Headers/CSP**: Inject a Content Security Policy via `<meta>` tag in the HTML wrapper:
+  - `default-src 'none'; style-src 'unsafe-inline'; img-src 'self' data:;` (Blocks all external assets by default).
+
+### Image Blocking Logic
+- **Initial State**: Block remote images by injecting a CSP that restricts `img-src` to `data:` and local schemes.
+- **Toggle Mechanism**:
+  - Provide a "Load Remote Images" button in the Flutter UI.
+  - When triggered, re-render the HTML with an updated CSP: `img-src * data:;`.
+
+### Link Interception & Phishing Protection
+- Implement `NavigationDelegate.onNavigationRequest`.
+- **Process**:
+  1. Intercept any URL that doesn't start with `about:blank` or `data:`.
+  2. Block the navigation in the WebView.
+  3. Trigger a Flutter `showDialog` for confirmation.
+- **Phishing Protection Dialog**:
+  - Show the full URL.
+  - **Bold the FQDN**: Parse the URL using `Uri.parse`.
+    - Example: `https://`**`important-bank.com`**`/login`
+  - "Open in Browser" button uses `url_launcher`.
+
+## 3. Integration Plan
+### Step 1: Initialization
+Modify `lib/main.dart` to initialize the Linux WebView platform (using `webview_flutter_linux` or similar) during app startup.
+
+### Step 2: Replace Renderer in Screens
+- **EmailDetailScreen**: Replace `Html(...)` with `SecureEmailWebView(html: body.htmlBody!)`.
+- **ThreadDetailScreen**: Replace `Html(...)` with `SecureEmailWebView(html: body.htmlBody!)`.
+- Remove `flutter_html` imports and dependencies once migration is complete.
+
+## 4. Verification & Security Audit
+- **Manual Tests**:
+  - Open emails with complex HTML layouts.
+  - Verify images are blocked initially.
+  - Verify "Load images" works.
+  - Click various links (http, https, mailto) and verify the confirmation dialog and FQDN bolding.
+- **Security Check**:
+  - Verify that `<script>` tags are not executed.
+  - Verify no network requests for external images occur before user consent (via DevTools or proxy).
+
+## 5. Potential Challenges
+- **Linux WebView Stability**: WebKitGTK on Linux can sometimes have rendering or sizing issues in Flutter.
+- **Scrolling**: Ensuring the WebView integrates smoothly into the `ListView` of the email detail screen (might require fixed height or `SizedBox`).

Taskfile.yml

@@ -331,6 +331,12 @@ tasks:
     cmds:
       - fvm dart run scripts/check_coverage.dart
 
+  check-coverage:
+    desc: Run unit+widget tests with coverage, then fail if the gate is not met
+    deps: [test]
+    cmds:
+      - task: coverage
+
   website-dev:
     desc: Run Hugo development server
     cmds:
@@ -361,8 +367,8 @@ tasks:
           ${SSH_USER}@${SSH_HOST}:public_html/
 
   check-fast:
-    desc: Pre-commit checks — analyze + unit tests + widget tests (no build, no integration)
-    deps: [analyze, test, check-hygiene]
+    desc: Pre-commit checks — analyze + unit+widget tests + coverage gate (no build, no integration)
+    deps: [analyze, check-coverage, check-hygiene]
 
   check-hygiene:
     desc: Verify that no forbidden files (like home dir config) are tracked

android/app/build.gradle.kts

@@ -13,6 +13,7 @@ android {
     compileOptions {
         sourceCompatibility = JavaVersion.VERSION_17
         targetCompatibility = JavaVersion.VERSION_17
+        isCoreLibraryDesugaringEnabled = true
     }
 
     kotlinOptions {
@@ -35,7 +36,7 @@ android {
         applicationId = "de.sharedinbox.mua"
         // You can update the following values to match your application needs.
         // For more information, see: https://flutter.dev/to/review-gradle-config.
-        minSdk = flutter.minSdkVersion
+        minSdk = 23
         targetSdk = flutter.targetSdkVersion
         versionCode = flutter.versionCode
         versionName = flutter.versionName
@@ -65,6 +66,8 @@ flutter {
 }
 
 dependencies {
+    // Required for flutter_local_notifications and other plugins that need Java 8+ APIs on API < 26.
+    coreLibraryDesugaring("com.android.tools:desugar_jdk_libs:2.1.4")
     // integration_test is a dev dependency; the Flutter plugin loader adds it as
     // debugImplementation only, but GeneratedPluginRegistrant.java (in src/main)
     // references its class in all variants. Make it available for release compilation

android/app/src/main/AndroidManifest.xml

@@ -1,5 +1,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android">
     <uses-permission android:name="android.permission.INTERNET"/>
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS"/>
+    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
+    <uses-permission android:name="android.permission.WAKE_LOCK"/>
     <application
         android:label="sharedinbox"
         android:name="${applicationName}"

flake.nix

@@ -84,6 +84,8 @@
             # python3 base + Google Play API client (for scripts/deploy_playstore.py)
             (python3.withPackages (ps: with ps; [
               google-api-python-client
+              google-auth-httplib2
+              httplib2
             ]))  # used by stalwart-dev/start and deploy_playstore.py
             fgj      # Codeberg/Forgejo CLI (like gh for GitHub)
           ]);

lib/core/models/draft.dart

@@ -7,6 +7,7 @@ class SavedDraft {
   final String subjectText;
   final String bodyText;
   final DateTime updatedAt;
+  final String? imapServerId;
 
   const SavedDraft({
     required this.id,
@@ -17,5 +18,6 @@ class SavedDraft {
     required this.subjectText,
     required this.bodyText,
     required this.updatedAt,
+    this.imapServerId,
   });
 }

lib/core/models/email.dart

@@ -21,6 +21,8 @@ class Email {
   final String? references;
   final DateTime? snoozedUntil;
   final String? snoozedFromMailboxPath;
+  // RFC 2369 List-Unsubscribe header value, e.g. "<mailto:...>, <https://...>".
+  final String? listUnsubscribeHeader;
 
   const Email({
     required this.id,
@@ -43,6 +45,7 @@ class Email {
     this.references,
     this.snoozedUntil,
     this.snoozedFromMailboxPath,
+    this.listUnsubscribeHeader,
   });
 
   factory Email.fromJson(Map<String, dynamic> json) {
@@ -77,6 +80,7 @@ class Email {
           ? DateTime.parse(json['snoozedUntil'] as String)
           : null,
       snoozedFromMailboxPath: json['snoozedFromMailboxPath'] as String?,
+      listUnsubscribeHeader: json['listUnsubscribeHeader'] as String?,
     );
   }
 
@@ -102,6 +106,7 @@ class Email {
       'references': references,
       'snoozedUntil': snoozedUntil?.toIso8601String(),
       'snoozedFromMailboxPath': snoozedFromMailboxPath,
+      'listUnsubscribeHeader': listUnsubscribeHeader,
     };
   }
 
@@ -126,6 +131,7 @@ class Email {
     String? references,
     DateTime? snoozedUntil,
     String? snoozedFromMailboxPath,
+    String? listUnsubscribeHeader,
   }) {
     return Email(
       id: id ?? this.id,
@@ -149,6 +155,8 @@ class Email {
       snoozedUntil: snoozedUntil ?? this.snoozedUntil,
       snoozedFromMailboxPath:
           snoozedFromMailboxPath ?? this.snoozedFromMailboxPath,
+      listUnsubscribeHeader:
+          listUnsubscribeHeader ?? this.listUnsubscribeHeader,
     );
   }
 }

lib/core/repositories/draft_repository.dart

@@ -21,4 +21,10 @@ abstract class DraftRepository {
 
   /// Permanently removes the draft with [id].
   Future<void> deleteDraft(int id);
+
+  /// Syncs local drafts with the server IMAP Drafts folder for [accountId].
+  /// Uploads local drafts that have no [SavedDraft.imapServerId]; imports
+  /// server drafts that are not already tracked locally.
+  /// No-op when the implementation has no IMAP connection configured.
+  Future<void> syncDrafts(String accountId, String password);
 }

lib/core/repositories/email_repository.dart

@@ -1,14 +1,19 @@
 import 'package:sharedinbox/core/models/email.dart';
 
 abstract class EmailRepository {
-  Stream<List<Email>> observeEmails(String accountId, String mailboxPath);
+  Stream<List<Email>> observeEmails(
+    String accountId,
+    String mailboxPath, {
+    int limit = 50,
+  });
 
   /// Groups emails by threadId and returns one [EmailThread] per thread,
   /// sorted by the latest message date descending.
   Stream<List<EmailThread>> observeThreads(
     String accountId,
-    String mailboxPath,
-  );
+    String mailboxPath, {
+    int limit = 50,
+  });
 
   /// Returns all emails belonging to [threadId] in [mailboxPath].
   Stream<List<Email>> observeEmailsInThread(

lib/core/repositories/search_history_repository.dart

@@ -0,0 +1,5 @@
+abstract interface class SearchHistoryRepository {
+  Future<List<String>> getRecentSearches();
+  Future<void> saveSearch(String query);
+  Future<void> clearHistory();
+}

lib/core/services/notification_service.dart

@@ -0,0 +1,38 @@
+import 'dart:io';
+
+import 'package:flutter_local_notifications/flutter_local_notifications.dart';
+
+const _kChannelId = 'new_mail';
+const _kChannelName = 'New mail';
+
+final _plugin = FlutterLocalNotificationsPlugin();
+
+Future<void> initNotifications() async {
+  const android = AndroidInitializationSettings('@mipmap/ic_launcher');
+  await _plugin.initialize(
+    const InitializationSettings(android: android),
+    onDidReceiveNotificationResponse: (_) {},
+  );
+  await _plugin
+      .resolvePlatformSpecificImplementation<
+          AndroidFlutterLocalNotificationsPlugin>()
+      ?.requestNotificationsPermission();
+}
+
+Future<void> showNewMailNotification(String accountEmail) async {
+  if (!Platform.isAndroid) return;
+  await _plugin.show(
+    accountEmail.hashCode & 0x7FFFFFFF,
+    'New mail',
+    accountEmail,
+    const NotificationDetails(
+      android: AndroidNotificationDetails(
+        _kChannelId,
+        _kChannelName,
+        channelDescription: 'Notifications for new incoming mail',
+        importance: Importance.high,
+        priority: Priority.high,
+      ),
+    ),
+  );
+}

lib/core/sync/account_sync_manager.dart

@@ -4,12 +4,16 @@ import 'package:enough_mail/enough_mail.dart' as imap;
 import 'package:sharedinbox/core/models/account.dart';
 import 'package:sharedinbox/core/models/email.dart' show SyncEmailsResult;
 import 'package:sharedinbox/core/repositories/account_repository.dart';
+import 'package:sharedinbox/core/repositories/draft_repository.dart';
 import 'package:sharedinbox/core/repositories/email_repository.dart';
 import 'package:sharedinbox/core/repositories/mailbox_repository.dart';
 import 'package:sharedinbox/core/repositories/sync_log_repository.dart';
 import 'package:sharedinbox/core/utils/logger.dart';
 import 'package:sharedinbox/data/imap/imap_client_factory.dart'
     show ImapConnectFn, connectImap, verboseLogKey;
+import 'package:sharedinbox/data/imap/tls_error.dart' show isTlsConfigError;
+
+typedef OnNewMailCallback = Future<void> Function(String accountEmail);
 
 /// Manages background sync for all accounts.
 ///
@@ -22,19 +26,35 @@ class AccountSyncManager {
     this._emails, {
     ImapConnectFn imapConnect = connectImap,
     SyncLogRepository syncLog = const NoOpSyncLogRepository(),
+    DraftRepository? drafts,
+    OnNewMailCallback? onNewMail,
   })  : _imapConnect = imapConnect,
-        _syncLog = syncLog;
+        _syncLog = syncLog,
+        _drafts = drafts,
+        _onNewMail = onNewMail;
 
   final AccountRepository _accounts;
   final MailboxRepository _mailboxes;
   final EmailRepository _emails;
   final ImapConnectFn _imapConnect;
   final SyncLogRepository _syncLog;
+  final DraftRepository? _drafts;
+  final OnNewMailCallback? _onNewMail;
 
   final Map<String, _SyncLoop> _active = {};
   StreamSubscription<List<Account>>? _accountsSub;
   StreamSubscription<String>? _onChangesSub;
 
+  final _syncPhaseCtrl = StreamController<(String, bool)>.broadcast();
+
+  /// Emits `true` when [accountId] starts syncing, `false` when it stops.
+  Stream<bool> watchSyncing(String accountId) =>
+      _syncPhaseCtrl.stream.where((e) => e.$1 == accountId).map((e) => e.$2);
+
+  void _emitSyncing(String accountId, {required bool syncing}) {
+    if (!_syncPhaseCtrl.isClosed) _syncPhaseCtrl.add((accountId, syncing));
+  }
+
   void start() {
     _onChangesSub = _emails.onChangesQueued.listen((accountId) {
       _active[accountId]?.kick();
@@ -45,6 +65,7 @@ class AccountSyncManager {
 
       for (final account in accounts) {
         if (_active.containsKey(account.id)) continue;
+        final id = account.id;
         final loop = switch (account.type) {
           AccountType.imap => _AccountSync(
               account,
@@ -53,6 +74,10 @@ class AccountSyncManager {
               _emails,
               _imapConnect,
               _syncLog,
+              _drafts,
+              _onNewMail,
+              onSyncStart: () => _emitSyncing(id, syncing: true),
+              onSyncEnd: () => _emitSyncing(id, syncing: false),
             ),
           AccountType.jmap => _JmapAccountSync(
               account,
@@ -60,6 +85,8 @@ class AccountSyncManager {
               _emails,
               _accounts,
               _syncLog,
+              onSyncStart: () => _emitSyncing(id, syncing: true),
+              onSyncEnd: () => _emitSyncing(id, syncing: false),
             ),
         };
         _active[account.id] = loop;
@@ -81,6 +108,7 @@ class AccountSyncManager {
       s.stop();
     }
     _active.clear();
+    unawaited(_syncPhaseCtrl.close());
   }
 
   /// Wakes the idle/wait phase of the given account's sync loop so a new
@@ -113,6 +141,10 @@ class AccountSyncManager {
           _emails,
           _imapConnect,
           _syncLog,
+          _drafts,
+          _onNewMail,
+          onSyncStart: () => _emitSyncing(accountId, syncing: true),
+          onSyncEnd: () => _emitSyncing(accountId, syncing: false),
         ),
       AccountType.jmap => _JmapAccountSync(
           account,
@@ -120,6 +152,8 @@ class AccountSyncManager {
           _emails,
           _accounts,
           _syncLog,
+          onSyncStart: () => _emitSyncing(accountId, syncing: true),
+          onSyncEnd: () => _emitSyncing(accountId, syncing: false),
         ),
     };
     _active[accountId] = loop;
@@ -145,7 +179,12 @@ class _AccountSync implements _SyncLoop {
     this._emails,
     this._imapConnect,
     this._syncLog,
-  );
+    this._drafts,
+    this._onNewMail, {
+    void Function()? onSyncStart,
+    void Function()? onSyncEnd,
+  })  : _onSyncStart = onSyncStart,
+        _onSyncEnd = onSyncEnd;
 
   final Account account;
   final AccountRepository _accounts;
@@ -153,6 +192,10 @@ class _AccountSync implements _SyncLoop {
   final EmailRepository _emails;
   final ImapConnectFn _imapConnect;
   final SyncLogRepository _syncLog;
+  final DraftRepository? _drafts;
+  final OnNewMailCallback? _onNewMail;
+  final void Function()? _onSyncStart;
+  final void Function()? _onSyncEnd;
 
   imap.ImapClient? _idleClient;
   bool _running = false;
@@ -185,6 +228,7 @@ class _AccountSync implements _SyncLoop {
   Future<void> _loop() async {
     while (_running) {
       final startedAt = DateTime.now();
+      _onSyncStart?.call();
       try {
         final (_SyncStats stats, String? capturedLog) = await _runSync(
           account.verbose,
@@ -204,8 +248,10 @@ class _AccountSync implements _SyncLoop {
           protocolLog: capturedLog,
         );
         _backoffSeconds = 5;
+        _onSyncEnd?.call();
         await _idle();
       } catch (e, st) {
+        _onSyncEnd?.call();
         final isPermanent = _isPermanentError(e);
         try {
           await _syncLog.log(
@@ -246,6 +292,7 @@ class _AccountSync implements _SyncLoop {
   }
 
   bool _isPermanentError(Object e) {
+    if (isTlsConfigError(e)) return true;
     final s = e.toString().toLowerCase();
     // enough_mail doesn't always have typed exceptions for auth, so we check strings.
     return s.contains('invalid credentials') ||
@@ -279,6 +326,8 @@ class _AccountSync implements _SyncLoop {
   Future<_SyncStats> _sync() async {
     final password = await _accounts.getPassword(account.id);
 
+    await _drafts?.syncDrafts(account.id, password);
+
     // Check for expired snoozes and move them back to Inbox before syncing.
     await _emails.wakeUpEmails(account.id);
 
@@ -325,6 +374,7 @@ class _AccountSync implements _SyncLoop {
       await client.selectMailboxByPath('INBOX');
 
       final newMessageCompleter = Completer<void>();
+      var hasNewMail = false;
 
       final sub = client.eventBus
           .on<imap.ImapEvent>()
@@ -332,7 +382,11 @@ class _AccountSync implements _SyncLoop {
             (e) =>
                 e is imap.ImapMessagesExistEvent || e is imap.ImapExpungeEvent,
           )
-          .listen((_) {
+          .listen((e) {
+        if (e is imap.ImapMessagesExistEvent &&
+            e.newMessagesExists > e.oldMessagesExists) {
+          hasNewMail = true;
+        }
         if (!newMessageCompleter.isCompleted) newMessageCompleter.complete();
       });
 
@@ -348,6 +402,10 @@ class _AccountSync implements _SyncLoop {
 
       await client.idleDone();
       await sub.cancel();
+
+      if (hasNewMail) {
+        unawaited(_onNewMail?.call(account.email));
+      }
     } finally {
       await client.logout();
       _idleClient = null;
@@ -364,14 +422,19 @@ class _JmapAccountSync implements _SyncLoop {
     this._mailboxes,
     this._emails,
     this._accounts,
-    this._syncLog,
-  );
+    this._syncLog, {
+    void Function()? onSyncStart,
+    void Function()? onSyncEnd,
+  })  : _onSyncStart = onSyncStart,
+        _onSyncEnd = onSyncEnd;
 
   final Account account;
   final MailboxRepository _mailboxes;
   final EmailRepository _emails;
   final AccountRepository _accounts;
   final SyncLogRepository _syncLog;
+  final void Function()? _onSyncStart;
+  final void Function()? _onSyncEnd;
 
   bool _running = false;
   int _backoffSeconds = 5;
@@ -403,6 +466,7 @@ class _JmapAccountSync implements _SyncLoop {
   Future<void> _loop() async {
     while (_running) {
       final startedAt = DateTime.now();
+      _onSyncStart?.call();
       try {
         final (_SyncStats stats, String? capturedLog) = await _runSync(
           account.verbose,
@@ -422,8 +486,10 @@ class _JmapAccountSync implements _SyncLoop {
           protocolLog: capturedLog,
         );
         _backoffSeconds = 5;
+        _onSyncEnd?.call();
         await _wait();
       } catch (e, st) {
+        _onSyncEnd?.call();
         final isPermanent = _isPermanentError(e);
         try {
           await _syncLog.log(
@@ -464,6 +530,7 @@ class _JmapAccountSync implements _SyncLoop {
   }
 
   bool _isPermanentError(Object e) {
+    if (isTlsConfigError(e)) return true;
     final s = e.toString().toLowerCase();
     return s.contains('invalid credentials') ||
         s.contains('authentication failed') ||

lib/core/sync/background_sync.dart

@@ -0,0 +1,123 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:drift/drift.dart';
+import 'package:drift/native.dart';
+import 'package:enough_mail/enough_mail.dart' as imap;
+import 'package:path/path.dart' as p;
+import 'package:path_provider/path_provider.dart';
+
+import 'package:sharedinbox/core/models/account.dart' as model;
+import 'package:sharedinbox/core/repositories/account_repository.dart';
+import 'package:sharedinbox/core/services/notification_service.dart';
+import 'package:sharedinbox/data/db/database.dart';
+import 'package:sharedinbox/data/imap/imap_client_factory.dart';
+import 'package:sharedinbox/data/repositories/account_repository_impl.dart';
+import 'package:sharedinbox/data/storage/flutter_secure_storage_impl.dart';
+
+import 'package:workmanager/workmanager.dart';
+
+const _kTaskName = 'si_bg_sync';
+const _kResourceType = 'background_check';
+
+@pragma('vm:entry-point')
+void callbackDispatcher() {
+  Workmanager().executeTask((_, __) async {
+    try {
+      await _doBackgroundSync();
+    } catch (_) {}
+    return true;
+  });
+}
+
+Future<void> registerBackgroundSync() async {
+  await Workmanager().initialize(callbackDispatcher);
+  await Workmanager().registerPeriodicTask(
+    _kTaskName,
+    _kTaskName,
+    frequency: const Duration(minutes: 15),
+    constraints: Constraints(networkType: NetworkType.connected),
+    existingWorkPolicy: ExistingPeriodicWorkPolicy.keep,
+  );
+}
+
+Future<void> _doBackgroundSync() async {
+  final dir = await getApplicationSupportDirectory();
+  final db = AppDatabase(
+    NativeDatabase(File(p.join(dir.path, 'sharedinbox.db'))),
+  );
+  try {
+    final accountRepo = AccountRepositoryImpl(
+      db,
+      const FlutterSecureStorageImpl(),
+    );
+    final accounts = await accountRepo.observeAccounts().first;
+    await initNotifications();
+    for (final account in accounts) {
+      if (account.type != model.AccountType.imap) continue;
+      await _checkAccount(db, accountRepo, account);
+    }
+  } finally {
+    await db.close();
+  }
+}
+
+Future<void> _checkAccount(
+  AppDatabase db,
+  AccountRepository accountRepo,
+  model.Account account,
+) async {
+  try {
+    final password = await accountRepo.getPassword(account.id);
+    final username =
+        account.username.isNotEmpty ? account.username : account.email;
+    final client = await connectImap(account, username, password);
+    try {
+      final status = await client.statusMailbox(
+        imap.Mailbox.virtual('INBOX', []),
+        [imap.StatusFlags.uidNext],
+      );
+      final currentUidNext = status.uidNext;
+
+      final stored = await (db.select(db.syncStates)
+            ..where(
+              (t) =>
+                  t.accountId.equals(account.id) &
+                  t.resourceType.equals(_kResourceType),
+            ))
+          .getSingleOrNull();
+      final lastUidNext = _parseUidNext(stored?.state);
+
+      await db.into(db.syncStates).insertOnConflictUpdate(
+            SyncStatesCompanion.insert(
+              accountId: account.id,
+              resourceType: _kResourceType,
+              state: jsonEncode({'uidNext': currentUidNext}),
+              syncedAt: DateTime.now(),
+            ),
+          );
+
+      if (lastUidNext != null &&
+          currentUidNext != null &&
+          currentUidNext > lastUidNext) {
+        await showNewMailNotification(account.email);
+      }
+    } finally {
+      await client.logout();
+    }
+  } catch (_) {}
+}
+
+int? _parseUidNext(String? state) {
+  if (state == null) return null;
+  try {
+    final decoded = jsonDecode(state);
+    if (decoded is Map<String, Object?>) {
+      return decoded['uidNext'] as int?;
+    }
+    return null;
+  } catch (_) {
+    return null;
+  }
+}

lib/core/utils/host_utils.dart

@@ -2,3 +2,21 @@ bool isLocalhost(String host) {
   final h = host.trim().toLowerCase();
   return h == 'localhost' || h == '127.0.0.1' || h == '::1';
 }
+
+String? validateHostname(String? value) {
+  if (value == null || value.trim().isEmpty) return 'Required';
+  return _checkHostChars(value.trim());
+}
+
+String? validateOptionalHostname(String? value) {
+  if (value == null || value.trim().isEmpty) return null;
+  return _checkHostChars(value.trim());
+}
+
+String? _checkHostChars(String h) {
+  if (h.contains(RegExp(r'[@/\\]')) ||
+      h.codeUnits.any((c) => c < 32 || c == 127)) {
+    return 'Invalid hostname';
+  }
+  return null;
+}

lib/data/db/database.dart

@@ -88,6 +88,9 @@ class Emails extends Table {
   DateTimeColumn get snoozedUntil => dateTime().nullable()();
   TextColumn get snoozedFromMailboxPath => text().nullable()();
 
+  // Added in schema v23: RFC 2369 List-Unsubscribe header value.
+  TextColumn get listUnsubscribeHeader => text().nullable()();
+
   @override
   Set<Column> get primaryKey => {id};
 }
@@ -227,6 +230,15 @@ class Drafts extends Table {
   TextColumn get subjectText => text().withDefault(const Constant(''))();
   TextColumn get bodyText => text().withDefault(const Constant(''))();
   DateTimeColumn get updatedAt => dateTime()();
+  // Added in schema v24: IMAP UID string ("mailbox:uid") on the server.
+  TextColumn get imapServerId => text().nullable()();
+}
+
+@DataClassName('SearchHistoryRow')
+class SearchHistoryEntries extends Table {
+  IntColumn get id => integer().autoIncrement()();
+  TextColumn get query => text()();
+  DateTimeColumn get searchedAt => dateTime()();
 }
 
 @DataClassName('UndoActionRow')
@@ -258,16 +270,54 @@ class UndoActions extends Table {
     SyncLogMailboxes,
     SyncHealth,
     UndoActions,
+    SearchHistoryEntries,
   ],
 )
 class AppDatabase extends _$AppDatabase {
   AppDatabase([QueryExecutor? executor]) : super(executor ?? _openConnection());
 
   @override
-  int get schemaVersion => 22;
+  int get schemaVersion => 27;
+
+  Future<void> _createEmailFts() async {
+    await customStatement('''
+      CREATE VIRTUAL TABLE IF NOT EXISTS email_fts USING fts5(
+        subject, preview, from_json,
+        content='emails',
+        content_rowid='rowid'
+      )
+    ''');
+    await customStatement('''
+      CREATE TRIGGER IF NOT EXISTS email_fts_ai
+      AFTER INSERT ON emails BEGIN
+        INSERT INTO email_fts(rowid, subject, preview, from_json)
+        VALUES (new.rowid, new.subject, new.preview, new.from_json);
+      END
+    ''');
+    await customStatement('''
+      CREATE TRIGGER IF NOT EXISTS email_fts_au
+      AFTER UPDATE OF subject, preview, from_json ON emails BEGIN
+        INSERT INTO email_fts(email_fts, rowid, subject, preview, from_json)
+        VALUES ('delete', old.rowid, old.subject, old.preview, old.from_json);
+        INSERT INTO email_fts(rowid, subject, preview, from_json)
+        VALUES (new.rowid, new.subject, new.preview, new.from_json);
+      END
+    ''');
+    await customStatement('''
+      CREATE TRIGGER IF NOT EXISTS email_fts_ad
+      AFTER DELETE ON emails BEGIN
+        INSERT INTO email_fts(email_fts, rowid, subject, preview, from_json)
+        VALUES ('delete', old.rowid, old.subject, old.preview, old.from_json);
+      END
+    ''');
+  }
 
   @override
   MigrationStrategy get migration => MigrationStrategy(
+        onCreate: (m) async {
+          await m.createAll();
+          await _createEmailFts();
+        },
         onUpgrade: (m, from, to) async {
           // NOTE: m.createTable(T) creates the LATEST version of table T.
           // If you later add a column C to T in version X, you must guard
@@ -420,6 +470,39 @@ class AppDatabase extends _$AppDatabase {
               ),
             );
           }
+          if (from < 23) {
+            await m.addColumn(emails, emails.listUnsubscribeHeader);
+          }
+          if (from >= 4 && from < 24) {
+            await m.addColumn(drafts, drafts.imapServerId);
+          }
+          if (from < 25) {
+            // For observeMailboxes: filter by account_id, sort by path.
+            await m.createIndex(
+              Index(
+                'mailboxes_account_id',
+                'CREATE INDEX IF NOT EXISTS mailboxes_account_id ON mailboxes (account_id, path);',
+              ),
+            );
+            // For observeThreads: filter by account_id+mailbox_path, sort by latest_date.
+            await m.createIndex(
+              Index(
+                'threads_latest_date',
+                'CREATE INDEX IF NOT EXISTS threads_latest_date ON threads (account_id, mailbox_path, latest_date DESC);',
+              ),
+            );
+          }
+          if (from < 26) {
+            await _createEmailFts();
+            // Backfill FTS index from existing rows.
+            await customStatement('''
+              INSERT INTO email_fts(rowid, subject, preview, from_json)
+              SELECT rowid, subject, preview, from_json FROM emails
+            ''');
+          }
+          if (from < 27) {
+            await m.createTable(searchHistoryEntries);
+          }
         },
       );
 }

lib/data/imap/tls_error.dart

@@ -21,15 +21,52 @@ class TlsModeMismatchException implements Exception {
       'STARTTLS). Original error: $original';
 }
 
-/// If [error] is a TLS handshake failure caused by a wrong-version-number
-/// (i.e. the server is not speaking TLS), throw a [TlsModeMismatchException]
-/// with [host]/[port] context. Otherwise rethrow [error] unchanged.
+/// Wraps a TLS certificate verification failure into a user-actionable message.
+///
+/// Thrown when the server's certificate cannot be verified — either because it
+/// is self-signed, expired, or the CA chain has changed since the account was
+/// set up.
+class TlsCertificateException implements Exception {
+  TlsCertificateException(this.host, this.port, this.original);
+  final String host;
+  final int port;
+  final Object original;
+
+  @override
+  String toString() =>
+      'TLS certificate error on $host:$port — the server certificate could '
+      'not be verified. The certificate may have changed or expired. '
+      'Please re-check your account settings or contact your mail provider. '
+      'Original error: $original';
+}
+
+/// Returns true if [error] is a permanent TLS configuration error that will
+/// not resolve on its own and requires user action.
+bool isTlsConfigError(Object error) =>
+    error is TlsModeMismatchException || error is TlsCertificateException;
+
+/// If [error] is a recognisable TLS handshake failure, wraps it in a typed
+/// exception and throws it.  Otherwise rethrows [error] unchanged.
+///
+/// Recognised patterns:
+/// - `WRONG_VERSION_NUMBER` → [TlsModeMismatchException] (port/mode mismatch)
+/// - `CERTIFICATE_VERIFY_FAILED` / `HandshakeException` → [TlsCertificateException]
 Never rethrowAsTlsHint(Object error, StackTrace stack, String host, int port) {
-  if (error.toString().contains('WRONG_VERSION_NUMBER')) {
+  final s = error.toString();
+  if (s.contains('WRONG_VERSION_NUMBER')) {
     Error.throwWithStackTrace(
       TlsModeMismatchException(host, port, error),
       stack,
     );
   }
+  if (s.contains('CERTIFICATE_VERIFY_FAILED') ||
+      s.contains('HandshakeException') ||
+      s.contains('CERTIFICATE_EXPIRED') ||
+      s.contains('CERTIFICATE_UNKNOWN')) {
+    Error.throwWithStackTrace(
+      TlsCertificateException(host, port, error),
+      stack,
+    );
+  }
   Error.throwWithStackTrace(error, stack);
 }

lib/data/repositories/draft_repository_impl.dart

@@ -1,13 +1,23 @@
 import 'package:drift/drift.dart';
+import 'package:enough_mail/enough_mail.dart' as imap;
 
+import 'package:sharedinbox/core/models/account.dart';
 import 'package:sharedinbox/core/models/draft.dart';
+import 'package:sharedinbox/core/repositories/account_repository.dart';
 import 'package:sharedinbox/core/repositories/draft_repository.dart';
 import 'package:sharedinbox/data/db/database.dart';
+import 'package:sharedinbox/data/imap/imap_client_factory.dart';
 
 class DraftRepositoryImpl implements DraftRepository {
-  DraftRepositoryImpl(this._db);
+  DraftRepositoryImpl(
+    this._db,
+    this._accounts, {
+    ImapConnectFn? imapConnect,
+  }) : _imapConnect = imapConnect;
 
   final AppDatabase _db;
+  final AccountRepository _accounts;
+  final ImapConnectFn? _imapConnect;
 
   @override
   Future<SavedDraft> saveDraft({
@@ -95,6 +105,110 @@ class DraftRepositoryImpl implements DraftRepository {
     await (_db.delete(_db.drafts)..where((t) => t.id.equals(id))).go();
   }
 
+  @override
+  Future<void> syncDrafts(String accountId, String password) async {
+    final connect = _imapConnect;
+    if (connect == null) return;
+
+    final account = await _accounts.getAccount(accountId);
+    if (account == null || account.type != AccountType.imap) return;
+
+    final username =
+        account.username.isNotEmpty ? account.username : account.email;
+    imap.ImapClient? client;
+    try {
+      client = await connect(account, username, password);
+      await _syncWithServer(client, accountId);
+    } finally {
+      await client?.logout();
+    }
+  }
+
+  Future<void> _syncWithServer(
+    imap.ImapClient client,
+    String accountId,
+  ) async {
+    // Create/select the Drafts folder.
+    try {
+      await client.createMailbox('Drafts');
+    } catch (_) {
+      // Already exists.
+    }
+    final selectResult = await client.selectMailboxByPath('Drafts');
+    final messageCount = selectResult.messagesExists;
+
+    // Upload local drafts that have no server counterpart.
+    final localDrafts = await (_db.select(_db.drafts)
+          ..where(
+            (t) => t.accountId.equals(accountId) & t.imapServerId.isNull(),
+          ))
+        .get();
+
+    for (final row in localDrafts) {
+      final builder = imap.MessageBuilder()
+        ..to = _parseAddresses(row.toText)
+        ..cc = _parseAddresses(row.ccText)
+        ..subject = row.subjectText
+        ..text = row.bodyText;
+      final mime = builder.buildMimeMessage();
+      final appendResult = await client.appendMessage(
+        mime,
+        targetMailboxPath: 'Drafts',
+        flags: [r'\Draft'],
+      );
+      final uidList =
+          appendResult.responseCodeAppendUid?.targetSequence.toList();
+      final uid = (uidList != null && uidList.isNotEmpty)
+          ? uidList.first.toString()
+          : null;
+      if (uid != null) {
+        await (_db.update(_db.drafts)..where((t) => t.id.equals(row.id)))
+            .write(DraftsCompanion(imapServerId: Value(uid)));
+      }
+    }
+
+    // Download server drafts not tracked locally.
+    if (messageCount > 0) {
+      final knownServerIds = await (_db.select(_db.drafts)
+            ..where(
+              (t) => t.accountId.equals(accountId) & t.imapServerId.isNotNull(),
+            ))
+          .get();
+      final knownIds = knownServerIds.map((r) => r.imapServerId!).toSet();
+
+      final seq = imap.MessageSequence.fromAll();
+      final fetch = await client.uidFetchMessages(seq, '(UID FLAGS ENVELOPE)');
+      for (final msg in fetch.messages) {
+        final uid = msg.uid?.toString();
+        if (uid == null || knownIds.contains(uid)) continue;
+        if (msg.flags?.contains(r'\Deleted') ?? false) continue;
+        final env = msg.envelope;
+        final now = DateTime.now();
+        await _db.into(_db.drafts).insert(
+              DraftsCompanion.insert(
+                accountId: Value(accountId),
+                toText: Value(_addressListToText(env?.to)),
+                ccText: Value(_addressListToText(env?.cc)),
+                subjectText: Value(env?.subject ?? ''),
+                bodyText: const Value(''),
+                updatedAt: now,
+                imapServerId: Value(uid),
+              ),
+            );
+      }
+    }
+  }
+
+  List<imap.MailAddress> _parseAddresses(String text) {
+    if (text.trim().isEmpty) return [];
+    return text.split(',').map((s) => imap.MailAddress('', s.trim())).toList();
+  }
+
+  String _addressListToText(List<imap.MailAddress>? addresses) {
+    if (addresses == null || addresses.isEmpty) return '';
+    return addresses.map((a) => a.email).join(', ');
+  }
+
   SavedDraft _toModel(Draft row) => SavedDraft(
         id: row.id,
         accountId: row.accountId,
@@ -104,5 +218,6 @@ class DraftRepositoryImpl implements DraftRepository {
         subjectText: row.subjectText,
         bodyText: row.bodyText,
         updatedAt: row.updatedAt,
+        imapServerId: row.imapServerId,
       );
 }

lib/data/repositories/email_repository_impl.dart

@@ -58,15 +58,17 @@ class EmailRepositoryImpl implements EmailRepository {
   @override
   Stream<List<model.Email>> observeEmails(
     String accountId,
-    String mailboxPath,
-  ) {
+    String mailboxPath, {
+    int limit = 50,
+  }) {
     return (_db.select(_db.emails)
           ..where(
             (t) =>
                 t.accountId.equals(accountId) &
                 t.mailboxPath.equals(mailboxPath),
           )
-          ..orderBy([(t) => OrderingTerm.desc(t.receivedAt)]))
+          ..orderBy([(t) => OrderingTerm.desc(t.receivedAt)])
+          ..limit(limit))
         .watch()
         .map((rows) => rows.map(_toModel).toList());
   }
@@ -74,15 +76,17 @@ class EmailRepositoryImpl implements EmailRepository {
   @override
   Stream<List<model.EmailThread>> observeThreads(
     String accountId,
-    String mailboxPath,
-  ) {
+    String mailboxPath, {
+    int limit = 50,
+  }) {
     return (_db.select(_db.threads)
           ..where(
             (t) =>
                 t.accountId.equals(accountId) &
                 t.mailboxPath.equals(mailboxPath),
           )
-          ..orderBy([(t) => OrderingTerm.desc(t.latestDate)]))
+          ..orderBy([(t) => OrderingTerm.desc(t.latestDate)])
+          ..limit(limit))
         .watch()
         .map((rows) => rows.map(_threadRowToModel).toList());
   }
@@ -528,7 +532,7 @@ class EmailRepositoryImpl implements EmailRepository {
     imap.MessageSequence sequence,
   ) async {
     const fetchItems =
-        '(UID FLAGS ENVELOPE BODYSTRUCTURE RFC822.SIZE BODY.PEEK[HEADER.FIELDS (REFERENCES)])';
+        '(UID FLAGS ENVELOPE BODYSTRUCTURE RFC822.SIZE BODY.PEEK[HEADER.FIELDS (REFERENCES LIST-UNSUBSCRIBE)])';
     final fetch = sequence.isUidSequence
         ? await client.uidFetchMessages(sequence, fetchItems)
         : await client.fetchMessages(sequence, fetchItems);
@@ -569,6 +573,7 @@ class EmailRepositoryImpl implements EmailRepository {
         final msgId = envelope.messageId?.trim();
         final inReplyTo = envelope.inReplyTo?.trim();
         final refs = msg.getHeaderValue('References')?.trim();
+        final listUnsubscribe = msg.getHeaderValue('List-Unsubscribe')?.trim();
         final threadId = _computeThreadId(
               emailId: emailId,
               messageId: msgId,
@@ -612,6 +617,7 @@ class EmailRepositoryImpl implements EmailRepository {
                 inReplyTo: Value(inReplyTo),
                 references: Value(refs),
                 snoozedUntil: Value(snoozedUntil),
+                listUnsubscribeHeader: Value(listUnsubscribe),
               ),
             );
       }
@@ -950,6 +956,7 @@ class EmailRepositoryImpl implements EmailRepository {
     'htmlBody',
     'bodyValues',
     'attachments',
+    'header:List-Unsubscribe:asText',
   ];
 
   static const _emailGetBodyOptions = {
@@ -1151,6 +1158,8 @@ class EmailRepositoryImpl implements EmailRepository {
       final jmapReferences = _joinJmapStringList(
         m['references'] as List<dynamic>?,
       );
+      final jmapListUnsubscribe =
+          (m['header:List-Unsubscribe:asText'] as String?)?.trim();
 
       await _db.into(_db.emails).insertOnConflictUpdate(
             EmailsCompanion.insert(
@@ -1173,6 +1182,7 @@ class EmailRepositoryImpl implements EmailRepository {
               inReplyTo: Value(jmapInReplyTo),
               references: Value(jmapReferences),
               snoozedUntil: Value(snoozedUntil),
+              listUnsubscribeHeader: Value(jmapListUnsubscribe),
             ),
           );
 
@@ -2464,28 +2474,39 @@ class EmailRepositoryImpl implements EmailRepository {
     String? accountId,
     String query,
   ) async {
+    final ftsQuery = _toFtsQuery(query);
+    if (ftsQuery.isEmpty) return [];
+
+    final sql = accountId != null
+        ? 'SELECT e.* FROM email_fts f JOIN emails e ON e.rowid = f.rowid'
+            ' WHERE email_fts MATCH ? AND e.account_id = ? ORDER BY rank LIMIT 50'
+        : 'SELECT e.* FROM email_fts f JOIN emails e ON e.rowid = f.rowid'
+            ' WHERE email_fts MATCH ? ORDER BY rank LIMIT 50';
+    final variables = accountId != null
+        ? [Variable<String>(ftsQuery), Variable<String>(accountId)]
+        : [Variable<String>(ftsQuery)];
+
+    final queryRows = await _db
+        .customSelect(sql, variables: variables, readsFrom: {_db.emails}).get();
+    final emailRows = await Future.wait(
+      queryRows.map((r) => _db.emails.mapFromRow(r)),
+    );
+    return emailRows.map(_toModel).toList();
+  }
+
+  /// Converts a user query string into an FTS5 match expression.
+  /// Each whitespace-separated word becomes a prefix term (word*) so that
+  /// partial words still match. Special FTS5 characters are stripped.
+  static String _toFtsQuery(String query) {
     final words = query
-        .toLowerCase()
+        .trim()
         .split(RegExp(r'\s+'))
         .where((w) => w.isNotEmpty)
+        .map((w) => w.replaceAll(RegExp(r'[^\w]'), ''))
+        .where((w) => w.isNotEmpty)
         .toList();
-    final rows = await (_db.select(_db.emails)
-          ..where((t) {
-            Expression<bool> condition = const Constant(true);
-            if (accountId != null) {
-              condition = t.accountId.equals(accountId);
-            }
-            for (final word in words) {
-              final pattern = '%$word%';
-              condition = condition &
-                  (t.subject.like(pattern) | t.preview.like(pattern));
-            }
-            return condition;
-          })
-          ..orderBy([(t) => OrderingTerm.desc(t.receivedAt)])
-          ..limit(50))
-        .get();
-    return rows.map(_toModel).toList();
+    if (words.isEmpty) return '';
+    return words.map((w) => '$w*').join(' ');
   }
 
   @override
@@ -2663,6 +2684,7 @@ class EmailRepositoryImpl implements EmailRepository {
       references: row.references,
       snoozedUntil: row.snoozedUntil,
       snoozedFromMailboxPath: row.snoozedFromMailboxPath,
+      listUnsubscribeHeader: row.listUnsubscribeHeader,
     );
   }
 

lib/data/repositories/search_history_repository_impl.dart

@@ -0,0 +1,57 @@
+import 'package:drift/drift.dart';
+import 'package:sharedinbox/core/repositories/search_history_repository.dart';
+import 'package:sharedinbox/data/db/database.dart';
+
+class SearchHistoryRepositoryImpl implements SearchHistoryRepository {
+  SearchHistoryRepositoryImpl(this._db);
+  final AppDatabase _db;
+
+  static const _maxEntries = 10;
+
+  @override
+  Future<List<String>> getRecentSearches() async {
+    final rows = await (_db.select(_db.searchHistoryEntries)
+          ..orderBy([(t) => OrderingTerm.desc(t.searchedAt)])
+          ..limit(_maxEntries))
+        .get();
+    return rows.map((r) => r.query).toList();
+  }
+
+  @override
+  Future<void> saveSearch(String query) async {
+    final trimmed = query.trim();
+    if (trimmed.isEmpty) return;
+
+    await _db.transaction(() async {
+      // Remove existing entry for same query (deduplication).
+      await (_db.delete(_db.searchHistoryEntries)
+            ..where((t) => t.query.equals(trimmed)))
+          .go();
+
+      await _db.into(_db.searchHistoryEntries).insert(
+            SearchHistoryEntriesCompanion.insert(
+              query: trimmed,
+              searchedAt: DateTime.now(),
+            ),
+          );
+
+      // Prune to the most recent _maxEntries.
+      final keepIds = await (_db.select(_db.searchHistoryEntries)
+            ..orderBy([(t) => OrderingTerm.desc(t.searchedAt)])
+            ..limit(_maxEntries))
+          .map((r) => r.id)
+          .get();
+
+      if (keepIds.isNotEmpty) {
+        await (_db.delete(_db.searchHistoryEntries)
+              ..where((t) => t.id.isNotIn(keepIds)))
+            .go();
+      }
+    });
+  }
+
+  @override
+  Future<void> clearHistory() async {
+    await _db.delete(_db.searchHistoryEntries).go();
+  }
+}

lib/di.dart

@@ -3,26 +3,30 @@ import 'dart:async';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:http/http.dart' as http;
 import 'package:sharedinbox/core/models/account.dart' as model;
+import 'package:sharedinbox/core/models/email.dart';
 import 'package:sharedinbox/core/models/undo_action.dart';
 import 'package:sharedinbox/core/repositories/account_repository.dart';
 import 'package:sharedinbox/core/repositories/draft_repository.dart';
 import 'package:sharedinbox/core/repositories/email_repository.dart';
 import 'package:sharedinbox/core/repositories/mailbox_repository.dart';
+import 'package:sharedinbox/core/repositories/search_history_repository.dart';
 import 'package:sharedinbox/core/repositories/undo_repository.dart';
 import 'package:sharedinbox/core/services/account_discovery_service.dart';
 import 'package:sharedinbox/core/services/connection_test_service.dart';
 import 'package:sharedinbox/core/services/managesieve_probe_service.dart';
+import 'package:sharedinbox/core/services/notification_service.dart';
 import 'package:sharedinbox/core/services/undo_service.dart';
 import 'package:sharedinbox/core/storage/secure_storage.dart';
 import 'package:sharedinbox/core/sync/account_sync_manager.dart';
 import 'package:sharedinbox/core/sync/reliability_runner.dart';
-import 'package:sharedinbox/data/db/database.dart';
+import 'package:sharedinbox/data/db/database.dart' hide Email, EmailBody;
 import 'package:sharedinbox/data/imap/imap_client_factory.dart';
 import 'package:sharedinbox/data/jmap/sieve_repository.dart';
 import 'package:sharedinbox/data/repositories/account_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/draft_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/email_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/mailbox_repository_impl.dart';
+import 'package:sharedinbox/data/repositories/search_history_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/sync_log_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/undo_repository_impl.dart';
 import 'package:sharedinbox/data/storage/flutter_secure_storage_impl.dart';
@@ -65,7 +69,11 @@ final mailboxRepositoryProvider = Provider<MailboxRepository>((ref) {
 });
 
 final draftRepositoryProvider = Provider<DraftRepository>((ref) {
-  return DraftRepositoryImpl(ref.watch(dbProvider));
+  return DraftRepositoryImpl(
+    ref.watch(dbProvider),
+    ref.watch(accountRepositoryProvider),
+    imapConnect: ref.watch(imapConnectProvider),
+  );
 });
 
 final emailRepositoryProvider = Provider<EmailRepository>((ref) {
@@ -81,6 +89,11 @@ final undoRepositoryProvider = Provider<UndoRepository>((ref) {
   return UndoRepositoryImpl(ref.watch(dbProvider));
 });
 
+final searchHistoryRepositoryProvider =
+    Provider<SearchHistoryRepository>((ref) {
+  return SearchHistoryRepositoryImpl(ref.watch(dbProvider));
+});
+
 final syncLogRepositoryProvider = Provider((ref) {
   return SyncLogRepositoryImpl(ref.watch(dbProvider));
 });
@@ -110,6 +123,11 @@ final syncHealthProvider =
       .watchSingleOrNull();
 });
 
+final isSyncingProvider =
+    StreamProvider.autoDispose.family<bool, String>((ref, accountId) {
+  return ref.watch(syncManagerProvider).watchSyncing(accountId);
+});
+
 final syncManagerProvider = Provider<AccountSyncManager>((ref) {
   final manager = AccountSyncManager(
     ref.watch(accountRepositoryProvider),
@@ -117,6 +135,8 @@ final syncManagerProvider = Provider<AccountSyncManager>((ref) {
     ref.watch(emailRepositoryProvider),
     syncLog: ref.watch(syncLogRepositoryProvider),
     imapConnect: ref.watch(imapConnectProvider),
+    drafts: ref.watch(draftRepositoryProvider),
+    onNewMail: showNewMailNotification,
   );
   ref.onDispose(manager.dispose);
   return manager;
@@ -156,6 +176,27 @@ final undoServiceProvider =
   return service;
 });
 
+/// Loads email header + body and marks the email as seen.
+/// Owned by [EmailDetailScreen]; decouples data loading from the widget tree.
+final emailDetailProvider = AsyncNotifierProvider.autoDispose
+    .family<EmailDetailNotifier, (Email?, EmailBody), String>(
+  EmailDetailNotifier.new,
+);
+
+class EmailDetailNotifier
+    extends AutoDisposeFamilyAsyncNotifier<(Email?, EmailBody), String> {
+  @override
+  Future<(Email?, EmailBody)> build(String emailId) async {
+    final repo = ref.read(emailRepositoryProvider);
+    final results = await Future.wait([
+      repo.getEmail(emailId),
+      repo.getEmailBody(emailId),
+    ]);
+    unawaited(repo.setFlag(emailId, seen: true));
+    return (results[0] as Email?, results[1] as EmailBody);
+  }
+}
+
 final accountByIdProvider =
     StreamProvider.autoDispose.family<model.Account?, String>((ref, accountId) {
   return ref.watch(accountRepositoryProvider).observeAccounts().map(

lib/main.dart

@@ -1,8 +1,11 @@
 import 'dart:async';
+import 'dart:io';
 
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
+import 'package:sharedinbox/core/services/notification_service.dart';
+import 'package:sharedinbox/core/sync/background_sync.dart';
 import 'package:sharedinbox/data/db/database.dart';
 import 'package:sharedinbox/di.dart';
 import 'package:sharedinbox/ui/router.dart';
@@ -32,6 +35,10 @@ void main({List<Override> overrides = const []}) async {
         };
 
         await initDatabasePath();
+        if (Platform.isAndroid) {
+          await initNotifications();
+          await registerBackgroundSync();
+        }
         runApp(
           ProviderScope(overrides: overrides, child: const SharedInboxApp()),
         );

lib/ui/screens/add_account_screen.dart

@@ -408,7 +408,7 @@ class _AddAccountScreenState extends ConsumerState<AddAccountScreen> {
             _field(_passwordCtrl, 'Password', obscure: true),
             const Divider(height: 32),
             Text('IMAP', style: Theme.of(context).textTheme.titleSmall),
-            _field(_imapHostCtrl, 'Host'),
+            _field(_imapHostCtrl, 'Host', validator: validateHostname),
             _field(_imapPortCtrl, 'Port', keyboardType: TextInputType.number),
             if (isLocalhost(_imapHostCtrl.text.trim()))
               SwitchListTile(
@@ -418,7 +418,7 @@ class _AddAccountScreenState extends ConsumerState<AddAccountScreen> {
               ),
             const Divider(height: 32),
             Text('SMTP', style: Theme.of(context).textTheme.titleSmall),
-            _field(_smtpHostCtrl, 'Host'),
+            _field(_smtpHostCtrl, 'Host', validator: validateHostname),
             _field(_smtpPortCtrl, 'Port', keyboardType: TextInputType.number),
             if (isLocalhost(_smtpHostCtrl.text.trim()))
               SwitchListTile(
@@ -475,6 +475,7 @@ class _AddAccountScreenState extends ConsumerState<AddAccountScreen> {
     bool obscure = false,
     bool required = true,
     TextInputType? keyboardType,
+    String? Function(String?)? validator,
   }) {
     return Padding(
       padding: const EdgeInsets.symmetric(vertical: 6),
@@ -486,9 +487,10 @@ class _AddAccountScreenState extends ConsumerState<AddAccountScreen> {
           labelText: label,
           border: const OutlineInputBorder(),
         ),
-        validator: required
-            ? (v) => (v == null || v.trim().isEmpty) ? 'Required' : null
-            : null,
+        validator: validator ??
+            (required
+                ? (v) => (v == null || v.trim().isEmpty) ? 'Required' : null
+                : null),
       ),
     );
   }

lib/ui/screens/edit_account_screen.dart

@@ -324,11 +324,11 @@ class _EditAccountScreenState extends ConsumerState<EditAccountScreen> {
                 'IMAP (SSL/TLS)',
                 style: Theme.of(context).textTheme.titleSmall,
               ),
-              _field(_imapHostCtrl, 'Host'),
+              _field(_imapHostCtrl, 'Host', validator: validateHostname),
               _field(_imapPortCtrl, 'Port', keyboardType: TextInputType.number),
               const Divider(height: 32),
               Text('SMTP', style: Theme.of(context).textTheme.titleSmall),
-              _field(_smtpHostCtrl, 'Host'),
+              _field(_smtpHostCtrl, 'Host', validator: validateHostname),
               _field(_smtpPortCtrl, 'Port', keyboardType: TextInputType.number),
               if (isLocalhost(_smtpHostCtrl.text.trim()))
                 SwitchListTile(
@@ -348,6 +348,7 @@ class _EditAccountScreenState extends ConsumerState<EditAccountScreen> {
                     _sieveHostCtrl,
                     'Host (leave blank to use IMAP host)',
                     required: false,
+                    validator: validateOptionalHostname,
                   ),
                   _field(
                     _sievePortCtrl,
@@ -408,6 +409,7 @@ class _EditAccountScreenState extends ConsumerState<EditAccountScreen> {
     bool obscure = false,
     bool required = true,
     TextInputType? keyboardType,
+    String? Function(String?)? validator,
   }) {
     return Padding(
       padding: const EdgeInsets.symmetric(vertical: 6),
@@ -420,9 +422,10 @@ class _EditAccountScreenState extends ConsumerState<EditAccountScreen> {
           labelText: label,
           border: const OutlineInputBorder(),
         ),
-        validator: required
-            ? (v) => (v == null || v.trim().isEmpty) ? 'Required' : null
-            : null,
+        validator: validator ??
+            (required
+                ? (v) => (v == null || v.trim().isEmpty) ? 'Required' : null
+                : null),
       ),
     );
   }

lib/ui/screens/email_detail_screen.dart

@@ -13,6 +13,7 @@ import 'package:sharedinbox/core/utils/format_utils.dart';
 import 'package:sharedinbox/core/utils/html_utils.dart';
 import 'package:sharedinbox/di.dart';
 import 'package:sharedinbox/ui/widgets/snooze_picker.dart';
+import 'package:url_launcher/url_launcher.dart';
 
 final _dateFmt = DateFormat('EEE, MMM d yyyy, HH:mm');
 
@@ -25,144 +26,130 @@ class EmailDetailScreen extends ConsumerStatefulWidget {
 }
 
 class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
-  late final Future<(Email?, EmailBody)> _dataFuture;
   bool _isFlagged = false;
   bool _loadRemoteImages = false;
   final Set<String> _downloading = {};
 
-  @override
-  void initState() {
-    super.initState();
-    final repo = ref.read(emailRepositoryProvider);
-    _dataFuture = Future.wait([
-      repo.getEmail(widget.emailId),
-      repo.getEmailBody(widget.emailId),
-    ]).then((results) {
-      final email = results[0] as Email?;
-      if (email != null && mounted) {
-        setState(() => _isFlagged = email.isFlagged);
-      }
-      return (email, results[1] as EmailBody);
-    });
-    unawaited(repo.setFlag(widget.emailId, seen: true));
-  }
-
   @override
   Widget build(BuildContext context) {
     final repo = ref.watch(emailRepositoryProvider);
-    return FutureBuilder<(Email?, EmailBody)>(
-      future: _dataFuture,
-      builder: (ctx, snap) {
-        final header = snap.data?.$1;
-        final body = snap.data?.$2;
+    final detail = ref.watch(emailDetailProvider(widget.emailId));
 
-        return Scaffold(
-          appBar: AppBar(
-            title: Text(
-              header?.subject ?? '(loading…)',
-              overflow: TextOverflow.ellipsis,
+    ref.listen<AsyncValue<(Email?, EmailBody)>>(
+      emailDetailProvider(widget.emailId),
+      (_, next) {
+        final email = next.valueOrNull?.$1;
+        if (email != null && mounted) {
+          setState(() => _isFlagged = email.isFlagged);
+        }
+      },
+    );
+
+    final header = detail.valueOrNull?.$1;
+    final body = detail.valueOrNull?.$2;
+
+    return Scaffold(
+      appBar: AppBar(
+        title: Text(
+          header?.subject ?? '(loading…)',
+          overflow: TextOverflow.ellipsis,
+        ),
+        actions: [
+          IconButton(
+            icon: const Icon(Icons.reply),
+            tooltip: 'Reply',
+            onPressed: header == null
+                ? null
+                : () => _reply(context, header, body, replyAll: false),
+          ),
+          IconButton(
+            icon: const Icon(Icons.reply_all),
+            tooltip: 'Reply all',
+            onPressed: header == null
+                ? null
+                : () => _reply(context, header, body, replyAll: true),
+          ),
+          IconButton(
+            icon: const Icon(Icons.forward),
+            tooltip: 'Forward',
+            onPressed:
+                header == null ? null : () => _forward(context, header, body),
+          ),
+          IconButton(
+            icon: const Icon(Icons.mark_email_unread_outlined),
+            tooltip: 'Mark as unread',
+            onPressed: () async {
+              await repo.setFlag(widget.emailId, seen: false);
+              if (context.mounted) context.pop();
+            },
+          ),
+          IconButton(
+            icon: Icon(
+              _isFlagged ? Icons.star : Icons.star_border,
+              color: _isFlagged ? Colors.amber : null,
             ),
-            actions: [
-              IconButton(
-                icon: const Icon(Icons.reply),
-                tooltip: 'Reply',
-                onPressed: header == null
-                    ? null
-                    : () => _reply(context, header, body, replyAll: false),
-              ),
-              IconButton(
-                icon: const Icon(Icons.reply_all),
-                tooltip: 'Reply all',
-                onPressed: header == null
-                    ? null
-                    : () => _reply(context, header, body, replyAll: true),
-              ),
-              IconButton(
-                icon: const Icon(Icons.forward),
-                tooltip: 'Forward',
-                onPressed: header == null
-                    ? null
-                    : () => _forward(context, header, body),
-              ),
-              IconButton(
-                icon: const Icon(Icons.mark_email_unread_outlined),
-                tooltip: 'Mark as unread',
-                onPressed: () async {
-                  await repo.setFlag(widget.emailId, seen: false);
-                  if (context.mounted) context.pop();
-                },
-              ),
-              IconButton(
-                icon: Icon(
-                  _isFlagged ? Icons.star : Icons.star_border,
-                  color: _isFlagged ? Colors.amber : null,
-                ),
-                tooltip: _isFlagged ? 'Unflag' : 'Flag',
-                onPressed: () async {
-                  final next = !_isFlagged;
-                  await repo.setFlag(widget.emailId, flagged: next);
-                  if (mounted) setState(() => _isFlagged = next);
-                },
-              ),
-              IconButton(
-                icon: const Icon(Icons.drive_file_move_outline),
-                tooltip: 'Move to folder',
-                onPressed:
-                    header == null ? null : () => _moveTo(context, header),
-              ),
-              IconButton(
-                icon: const Icon(Icons.access_time),
-                tooltip: 'Snooze',
-                onPressed:
-                    header == null ? null : () => _snooze(context, header),
-              ),
-              IconButton(
-                icon: const Icon(Icons.delete),
-                tooltip: 'Delete',
-                onPressed: () async {
-                  final destPath = await repo.deleteEmail(widget.emailId);
+            tooltip: _isFlagged ? 'Unflag' : 'Flag',
+            onPressed: () async {
+              final next = !_isFlagged;
+              await repo.setFlag(widget.emailId, flagged: next);
+              if (mounted) setState(() => _isFlagged = next);
+            },
+          ),
+          IconButton(
+            icon: const Icon(Icons.drive_file_move_outline),
+            tooltip: 'Move to folder',
+            onPressed: header == null ? null : () => _moveTo(context, header),
+          ),
+          IconButton(
+            icon: const Icon(Icons.access_time),
+            tooltip: 'Snooze',
+            onPressed: header == null ? null : () => _snooze(context, header),
+          ),
+          IconButton(
+            icon: const Icon(Icons.delete),
+            tooltip: 'Delete',
+            onPressed: () async {
+              final destPath = await repo.deleteEmail(widget.emailId);
 
-                  if (header != null) {
-                    unawaited(
-                      ref.read(undoServiceProvider.notifier).pushAction(
-                            UndoAction(
-                              id: DateTime.now().toIso8601String(),
-                              accountId: header.accountId,
-                              type: UndoType.delete,
-                              emailIds: [widget.emailId],
-                              sourceMailboxPath: header.mailboxPath,
-                              destinationMailboxPath: destPath,
-                              originalEmails: [header],
-                            ),
-                          ),
-                    );
-                  }
+              if (header != null) {
+                unawaited(
+                  ref.read(undoServiceProvider.notifier).pushAction(
+                        UndoAction(
+                          id: DateTime.now().toIso8601String(),
+                          accountId: header.accountId,
+                          type: UndoType.delete,
+                          emailIds: [widget.emailId],
+                          sourceMailboxPath: header.mailboxPath,
+                          destinationMailboxPath: destPath,
+                          originalEmails: [header],
+                        ),
+                      ),
+                );
+              }
 
-                  if (context.mounted) context.pop();
-                },
-              ),
-              PopupMenuButton<String>(
-                itemBuilder: (ctx) => [
-                  const PopupMenuItem(
-                    value: 'headers',
-                    child: Text('Show Mail Headers'),
-                  ),
-                ],
-                onSelected: (value) {
-                  if (value == 'headers' && body != null) {
-                    _showHeaders(context, body);
-                  }
-                },
+              if (context.mounted) context.pop();
+            },
+          ),
+          PopupMenuButton<String>(
+            itemBuilder: (ctx) => [
+              const PopupMenuItem(
+                value: 'headers',
+                child: Text('Show Mail Headers'),
               ),
             ],
+            onSelected: (value) {
+              if (value == 'headers' && body != null) {
+                _showHeaders(context, body);
+              }
+            },
           ),
-          body: snap.connectionState == ConnectionState.waiting
-              ? const Center(child: CircularProgressIndicator())
-              : snap.hasError
-                  ? Center(child: Text('Error: ${snap.error}'))
-                  : _buildBody(ctx, header, body!),
-        );
-      },
+        ],
+      ),
+      body: detail.when(
+        loading: () => const Center(child: CircularProgressIndicator()),
+        error: (e, _) => Center(child: Text('Error: $e')),
+        data: (d) => _buildBody(context, d.$1, d.$2),
+      ),
     );
   }
 
@@ -185,7 +172,7 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
                 ),
               ),
             ),
-          Html(
+          _SafeHtml(
             data: body.htmlBody!,
             extensions: [if (!_loadRemoteImages) _BlockRemoteImagesExtension()],
           ),
@@ -267,6 +254,11 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
             _dateFmt.format(email.sentAt!),
             style: Theme.of(ctx).textTheme.bodySmall,
           ),
+        if (email.listUnsubscribeHeader != null)
+          Padding(
+            padding: const EdgeInsets.only(top: 8),
+            child: _UnsubscribeChip(header: email.listUnsubscribeHeader!),
+          ),
       ],
     );
   }
@@ -462,6 +454,90 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
   }
 }
 
+/// Parses a List-Unsubscribe header and returns the first usable URI.
+/// Prefers mailto: so unsubscribing sends an email; falls back to https:.
+Uri? _parseUnsubscribeUri(String header) {
+  final matches = RegExp(r'<([^>]+)>').allMatches(header);
+  Uri? fallback;
+  for (final m in matches) {
+    final raw = m.group(1)!.trim();
+    final uri = Uri.tryParse(raw);
+    if (uri == null) continue;
+    if (uri.scheme == 'mailto') return uri;
+    if ((uri.scheme == 'https' || uri.scheme == 'http') && fallback == null) {
+      fallback = uri;
+    }
+  }
+  return fallback;
+}
+
+class _UnsubscribeChip extends StatelessWidget {
+  const _UnsubscribeChip({required this.header});
+  final String header;
+
+  @override
+  Widget build(BuildContext context) {
+    final uri = _parseUnsubscribeUri(header);
+    if (uri == null) return const SizedBox.shrink();
+    return ActionChip(
+      avatar: const Icon(Icons.unsubscribe_outlined, size: 16),
+      label: const Text('Unsubscribe'),
+      onPressed: () => launchUrl(uri, mode: LaunchMode.externalApplication),
+    );
+  }
+}
+
+/// Renders [Html] and falls back to an error message if the widget throws
+/// during build, preventing a malformed body from crashing the whole screen.
+class _SafeHtml extends StatefulWidget {
+  const _SafeHtml({required this.data, required this.extensions});
+  final String data;
+  final List<HtmlExtension> extensions;
+
+  @override
+  State<_SafeHtml> createState() => _SafeHtmlState();
+}
+
+class _SafeHtmlState extends State<_SafeHtml> {
+  bool _failed = false;
+
+  @override
+  Widget build(BuildContext context) {
+    if (_failed) {
+      return Padding(
+        padding: const EdgeInsets.all(8),
+        child: Row(
+          children: [
+            Icon(
+              Icons.warning_amber_outlined,
+              color: Theme.of(context).colorScheme.error,
+              size: 16,
+            ),
+            const SizedBox(width: 8),
+            const Expanded(child: Text('Message body could not be rendered.')),
+          ],
+        ),
+      );
+    }
+
+    // Intercept any build-phase throw from flutter_html for this subtree.
+    // We save/restore via postFrameCallback so other widgets are unaffected.
+    final prev = ErrorWidget.builder;
+    ErrorWidget.builder = (FlutterErrorDetails details) {
+      ErrorWidget.builder = prev;
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (mounted) setState(() => _failed = true);
+      });
+      return const SizedBox.shrink();
+    };
+    WidgetsBinding.instance.addPostFrameCallback(
+      (_) => ErrorWidget.builder = prev,
+    );
+
+    return Html(data: widget.data, extensions: widget.extensions);
+  }
+}
+
 class _BlockRemoteImagesExtension extends HtmlExtension {
   @override
   Set<String> get supportedTags => {'img'};

lib/ui/screens/email_list_screen.dart

@@ -10,6 +10,7 @@ import 'package:sharedinbox/core/models/email.dart';
 import 'package:sharedinbox/core/models/undo_action.dart';
 import 'package:sharedinbox/core/repositories/email_repository.dart';
 import 'package:sharedinbox/di.dart';
+import 'package:sharedinbox/ui/widgets/email_tile.dart';
 import 'package:sharedinbox/ui/widgets/folder_drawer.dart';
 import 'package:sharedinbox/ui/widgets/snooze_picker.dart';
 
@@ -44,6 +45,10 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
   List<EmailThread> _currentThreads = [];
   // Individual email selection used in search results.
   final Set<String> _selectedSearchIds = {};
+
+  // Pagination: number of threads currently requested from the DB.
+  static const _pageSize = 50;
+  int _limit = _pageSize;
   bool get _selecting =>
       _selectedThreadIds.isNotEmpty || _selectedSearchIds.isNotEmpty;
 
@@ -180,22 +185,7 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
                   ),
                 ),
               ),
-              IconButton(
-                icon: const Icon(Icons.sync),
-                onPressed: () async {
-                  try {
-                    await emailRepo.syncEmails(
-                      widget.accountId,
-                      widget.mailboxPath,
-                    );
-                  } catch (e) {
-                    if (!mounted) return;
-                    ScaffoldMessenger.of(
-                      context,
-                    ).showSnackBar(SnackBar(content: Text('Sync failed: $e')));
-                  }
-                },
-              ),
+              _buildSyncButton(emailRepo),
               IconButton(
                 icon: const Icon(Icons.edit),
                 onPressed: () => context.push(
@@ -229,6 +219,44 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
     );
   }
 
+  Widget _buildSyncButton(EmailRepository emailRepo) {
+    final isSyncing =
+        ref.watch(isSyncingProvider(widget.accountId)).valueOrNull ?? false;
+    final hasError =
+        ref.watch(syncLastErrorProvider(widget.accountId)).valueOrNull != null;
+    return IconButton(
+      tooltip: isSyncing
+          ? 'Syncing…'
+          : hasError
+              ? 'Sync error'
+              : 'Sync',
+      icon: isSyncing
+          ? const SizedBox(
+              width: 20,
+              height: 20,
+              child: CircularProgressIndicator(strokeWidth: 2),
+            )
+          : hasError
+              ? const Icon(Icons.sync_problem, color: Colors.red)
+              : const Icon(Icons.sync),
+      onPressed: isSyncing
+          ? null
+          : () async {
+              try {
+                await emailRepo.syncEmails(
+                  widget.accountId,
+                  widget.mailboxPath,
+                );
+              } catch (e) {
+                if (!mounted) return;
+                ScaffoldMessenger.of(context).showSnackBar(
+                  SnackBar(content: Text('Sync failed: $e')),
+                );
+              }
+            },
+    );
+  }
+
   Widget _selectionBottomBar() {
     return BottomAppBar(
       child: Row(
@@ -319,7 +347,11 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
         await emailRepo.syncEmails(widget.accountId, widget.mailboxPath);
       },
       child: StreamBuilder<List<EmailThread>>(
-        stream: emailRepo.observeThreads(widget.accountId, widget.mailboxPath),
+        stream: emailRepo.observeThreads(
+          widget.accountId,
+          widget.mailboxPath,
+          limit: _limit,
+        ),
         builder: (ctx, snap) {
           if (!snap.hasData) {
             return const Center(child: CircularProgressIndicator());
@@ -515,9 +547,16 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
   }
 
   Widget _buildThreadList(List<EmailThread> threads) {
+    final hasMore = threads.length == _limit;
     return ListView.builder(
-      itemCount: threads.length,
+      itemCount: threads.length + (hasMore ? 1 : 0),
       itemBuilder: (ctx, i) {
+        if (i == threads.length) {
+          return TextButton(
+            onPressed: () => setState(() => _limit += _pageSize),
+            child: const Text('Load more'),
+          );
+        }
         final t = threads[i];
         final isSelected = _selectedThreadIds.contains(t.threadId);
         final senderNames =
@@ -688,10 +727,9 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
       itemBuilder: (ctx, i) {
         final e = emails[i];
         final isSelected = _selectedSearchIds.contains(e.id);
-        final sender = e.from.isNotEmpty
-            ? (e.from.first.name ?? e.from.first.email)
-            : '(unknown)';
-        return ListTile(
+        return EmailTile(
+          email: e,
+          selected: isSelected,
           leading: SizedBox(
             width: 40,
             child: _selecting
@@ -699,25 +737,7 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
                     value: isSelected,
                     onChanged: (_) => _toggleSearchSelection(e.id),
                   )
-                : Icon(
-                    e.isSeen ? Icons.mail_outline : Icons.mail,
-                    color: e.isSeen ? null : Theme.of(ctx).colorScheme.primary,
-                  ),
-          ),
-          title: Text(
-            sender,
-            style:
-                e.isSeen ? null : const TextStyle(fontWeight: FontWeight.bold),
-          ),
-          subtitle: Text(
-            e.subject ?? '(no subject)',
-            maxLines: 1,
-            overflow: TextOverflow.ellipsis,
-          ),
-          selected: isSelected,
-          trailing: Text(
-            e.sentAt != null ? _dateFmt.format(e.sentAt!) : '',
-            style: Theme.of(ctx).textTheme.bodySmall,
+                : null,
           ),
           onTap: _selecting
               ? () => _toggleSearchSelection(e.id)

lib/ui/screens/search_screen.dart

@@ -8,6 +8,12 @@ import 'package:sharedinbox/core/models/email.dart';
 import 'package:sharedinbox/core/models/mailbox.dart';
 import 'package:sharedinbox/core/utils/logger.dart';
 import 'package:sharedinbox/di.dart';
+import 'package:sharedinbox/ui/widgets/email_tile.dart';
+
+final _searchHistoryProvider =
+    FutureProvider.autoDispose<List<String>>((ref) async {
+  return ref.watch(searchHistoryRepositoryProvider).getRecentSearches();
+});
 
 class SearchScreen extends ConsumerStatefulWidget {
   const SearchScreen({super.key, this.accountId});
@@ -19,13 +25,24 @@ class SearchScreen extends ConsumerStatefulWidget {
 
 class _SearchScreenState extends ConsumerState<SearchScreen> {
   final _ctrl = TextEditingController();
+  final _focusNode = FocusNode();
   Timer? _debounce;
   _SearchResults? _results;
   bool _loading = false;
+  bool _fieldFocused = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _focusNode.addListener(() {
+      if (mounted) setState(() => _fieldFocused = _focusNode.hasFocus);
+    });
+  }
 
   @override
   void dispose() {
     _ctrl.dispose();
+    _focusNode.dispose();
     _debounce?.cancel();
     super.dispose();
   }
@@ -44,6 +61,12 @@ class _SearchScreenState extends ConsumerState<SearchScreen> {
 
   Future<void> _search(String query) async {
     setState(() => _loading = true);
+    unawaited(
+      ref
+          .read(searchHistoryRepositoryProvider)
+          .saveSearch(query)
+          .then((_) => ref.invalidate(_searchHistoryProvider)),
+    );
     try {
       final emailRepo = ref.read(emailRepositoryProvider);
       final mailboxRepo = ref.read(mailboxRepositoryProvider);
@@ -111,6 +134,7 @@ class _SearchScreenState extends ConsumerState<SearchScreen> {
       appBar: AppBar(
         title: TextField(
           controller: _ctrl,
+          focusNode: _focusNode,
           autofocus: true,
           decoration: const InputDecoration(
             hintText: 'Search folders, addresses, emails…',
@@ -136,6 +160,9 @@ class _SearchScreenState extends ConsumerState<SearchScreen> {
   Widget _buildBody() {
     if (_loading) return const Center(child: CircularProgressIndicator());
     if (_results == null) {
+      if (_fieldFocused && _ctrl.text.isEmpty) {
+        return _buildHistoryPanel();
+      }
       return const Center(child: Text('Type 3+ characters to search'));
     }
     final r = _results!;
@@ -155,11 +182,79 @@ class _SearchScreenState extends ConsumerState<SearchScreen> {
         if (r.emails.isNotEmpty) ...[
           const _SectionHeader('Messages'),
           for (final e in r.emails)
-            _EmailTile(email: e, accountId: e.accountId),
+            EmailTile(
+              email: e,
+              showLocation: true,
+              onTap: () => context.push(
+                '/accounts/${e.accountId}/mailboxes'
+                '/${Uri.encodeComponent(e.mailboxPath)}'
+                '/emails/${Uri.encodeComponent(e.id)}',
+              ),
+            ),
         ],
       ],
     );
   }
+
+  Widget _buildHistoryPanel() {
+    final history = ref.watch(_searchHistoryProvider);
+    return history.when(
+      loading: () => const Center(child: Text('Type 3+ characters to search')),
+      error: (_, __) =>
+          const Center(child: Text('Type 3+ characters to search')),
+      data: (terms) {
+        if (terms.isEmpty) {
+          return const Center(child: Text('Type 3+ characters to search'));
+        }
+        return Column(
+          crossAxisAlignment: CrossAxisAlignment.start,
+          children: [
+            Padding(
+              padding: const EdgeInsets.fromLTRB(16, 12, 16, 4),
+              child: Row(
+                mainAxisAlignment: MainAxisAlignment.spaceBetween,
+                children: [
+                  Text(
+                    'Recent searches',
+                    style: Theme.of(context).textTheme.labelLarge,
+                  ),
+                  TextButton(
+                    onPressed: () async {
+                      await ref
+                          .read(searchHistoryRepositoryProvider)
+                          .clearHistory();
+                      ref.invalidate(_searchHistoryProvider);
+                    },
+                    child: const Text('Clear'),
+                  ),
+                ],
+              ),
+            ),
+            Padding(
+              padding: const EdgeInsets.symmetric(horizontal: 12),
+              child: Wrap(
+                spacing: 8,
+                runSpacing: 4,
+                children: [
+                  for (final term in terms)
+                    ActionChip(
+                      label: Text(term),
+                      onPressed: () {
+                        _ctrl.text = term;
+                        _ctrl.selection = TextSelection.fromPosition(
+                          TextPosition(offset: term.length),
+                        );
+                        unawaited(_search(term));
+                      },
+                    ),
+                ],
+              ),
+            ),
+          ],
+        );
+      },
+    );
+  }
 }
 
 class _SearchResults {
@@ -246,42 +341,3 @@ class _AddressTile extends StatelessWidget {
     );
   }
 }
-
-class _EmailTile extends StatelessWidget {
-  const _EmailTile({required this.email, required this.accountId});
-  final Email email;
-  final String accountId;
-
-  @override
-  Widget build(BuildContext context) {
-    final sender = email.from.isNotEmpty
-        ? (email.from.first.name ?? email.from.first.email)
-        : '(unknown)';
-    return ListTile(
-      leading: Icon(
-        email.isSeen ? Icons.mail_outline : Icons.mail,
-        color: email.isSeen ? null : Theme.of(context).colorScheme.primary,
-      ),
-      title: Text(sender),
-      subtitle: Column(
-        crossAxisAlignment: CrossAxisAlignment.start,
-        children: [
-          Text(
-            email.subject ?? '(no subject)',
-            maxLines: 1,
-            overflow: TextOverflow.ellipsis,
-          ),
-          Text(
-            '$accountId • ${email.mailboxPath}',
-            style: Theme.of(context).textTheme.bodySmall,
-          ),
-        ],
-      ),
-      onTap: () => context.push(
-        '/accounts/$accountId/mailboxes'
-        '/${Uri.encodeComponent(email.mailboxPath)}'
-        '/emails/${Uri.encodeComponent(email.id)}',
-      ),
-    );
-  }
-}

lib/ui/widgets/email_tile.dart

@@ -0,0 +1,74 @@
+import 'package:flutter/material.dart';
+import 'package:intl/intl.dart';
+
+import 'package:sharedinbox/core/models/email.dart';
+
+final _dateFmt = DateFormat('MMM d');
+
+/// A flat list tile for an individual [email].
+///
+/// Used in search-result lists and the per-mailbox search overlay.
+/// Pass a custom [leading] widget to support selection-mode checkboxes.
+class EmailTile extends StatelessWidget {
+  const EmailTile({
+    super.key,
+    required this.email,
+    required this.onTap,
+    this.leading,
+    this.selected = false,
+    this.onLongPress,
+    this.showLocation = false,
+  });
+
+  final Email email;
+  final VoidCallback onTap;
+  final Widget? leading;
+  final bool selected;
+  final VoidCallback? onLongPress;
+
+  /// When true, appends `accountId • mailboxPath` as a second subtitle line.
+  final bool showLocation;
+
+  @override
+  Widget build(BuildContext context) {
+    final sender = email.from.isNotEmpty
+        ? (email.from.first.name ?? email.from.first.email)
+        : '(unknown)';
+    final date = email.sentAt != null ? _dateFmt.format(email.sentAt!) : '';
+
+    return ListTile(
+      leading: leading ??
+          Icon(
+            email.isSeen ? Icons.mail_outline : Icons.mail,
+            color: email.isSeen ? null : Theme.of(context).colorScheme.primary,
+          ),
+      title: Text(
+        sender,
+        style:
+            email.isSeen ? null : const TextStyle(fontWeight: FontWeight.bold),
+        overflow: TextOverflow.ellipsis,
+      ),
+      subtitle: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Text(
+            email.subject ?? '(no subject)',
+            maxLines: 1,
+            overflow: TextOverflow.ellipsis,
+          ),
+          if (showLocation)
+            Text(
+              '${email.accountId} • ${email.mailboxPath}',
+              style: Theme.of(context).textTheme.bodySmall,
+            ),
+        ],
+      ),
+      trailing: date.isEmpty
+          ? null
+          : Text(date, style: Theme.of(context).textTheme.bodySmall),
+      selected: selected,
+      onTap: onTap,
+      onLongPress: onLongPress,
+    );
+  }
+}

plan-claude.md

@@ -0,0 +1,155 @@
+# SharedInbox — Improvement Plan
+
+30 tasks across 7 perspectives. Priority markers: 🔴 high · 🟡 medium · 🟢 nice-to-have.
+
+---
+
+## Group 1: Performance
+
+### P1 — Done: https://codeberg.org/guettli/sharedinbox/pulls/41
+
+### P1 🔴 Replace LIKE-based search with FTS5 virtual table
+The current `observeEmails` and search queries use `LIKE '%query%'` which becomes a full-table scan at scale.
+Create an `email_fts` FTS5 virtual table (subject, preview, fromJson) populated via trigger or sync-time insert.
+Wire `SearchScreen` to query the FTS table instead.
+Files: `lib/data/db/database.dart`, `lib/data/repositories/email_repository_impl.dart`.
+
+### P2 🔴 Lazy-load email bodies on scroll (pagination)
+`observeThreads` and `observeEmails` return the full list with no limit. As the mailbox grows this streams thousands of rows into memory.
+Add a page-size parameter (e.g. 50) with "load more" support in `EmailListScreen`.
+The `EmailBodies` table is already separate — never fetch bodies in the list query.
+Files: `lib/data/repositories/email_repository_impl.dart`, `lib/ui/screens/email_list_screen.dart`.
+
+### P3 🟡 Defer HTML parsing off the UI thread using an Isolate
+`flutter_html` parsing blocks the raster thread for large HTML bodies, causing jank when opening email detail.
+Move the HTML→Widget tree conversion (or at minimum the `html_utils.dart` HTML-to-plain step) into a `compute()` call.
+Files: `lib/ui/screens/email_detail_screen.dart`, `lib/core/utils/html_utils.dart`.
+
+### P4 — Done: https://codeberg.org/guettli/sharedinbox/pulls/36
+
+### P5 🟢 Cache the formatted date strings in EmailListScreen
+`DateFormat('MMM d').format(...)` is called for every email on every rebuild. Compute and cache these in the model layer or inside the list item widget's `build` method using a static cache map.
+Files: `lib/ui/screens/email_list_screen.dart`, `lib/core/utils/format_utils.dart`.
+
+---
+
+## Group 2: Reliability & Resilience
+
+### R1 — Done: https://codeberg.org/guettli/sharedinbox/pulls/20
+
+### R2 — Done: https://codeberg.org/guettli/sharedinbox/pulls/22
+
+### R3 — Done: https://codeberg.org/guettli/sharedinbox/pulls/35
+
+### R4 — Done: https://codeberg.org/guettli/sharedinbox/pulls/23
+
+### R5 — Done: https://codeberg.org/guettli/sharedinbox/pulls/45
+
+### R6 — Done: https://codeberg.org/guettli/sharedinbox/pulls/24
+
+---
+
+## Group 3: Security
+
+### S1 🔴 Optional SQLCipher encryption for the Drift database
+Emails cached locally are plaintext. Users on shared or rooted devices are exposed.
+Add an opt-in "Encrypt local storage" setting using `drift`'s `encrypted` backend (`sqflite_cipher` / `sqlcipher_flutter_libs`).
+Store the database key in `flutter_secure_storage` (already present).
+Files: `lib/data/db/database.dart`, `pubspec.yaml`, a new settings toggle.
+
+### S2 — Done: https://codeberg.org/guettli/sharedinbox/pulls/25
+
+### S3 🟡 Enforce certificate pinning for known providers (opt-in)
+Auto-discovered accounts for major providers (Gmail, Fastmail, Proton) could be pinned to their known CA hierarchy.
+Implement as an opt-in per-account setting; only applies when the account is auto-discovered via `AccountDiscoveryService`.
+Files: `lib/core/services/account_discovery_service.dart`, `lib/data/imap/imap_client_factory.dart`.
+
+### S4 🟢 Audit and restrict external link handling in HTML emails
+`flutter_html` passes `<a href>` clicks to `url_launcher` without a prompt.
+Before launching, show a confirmation dialog with the destination URL so phishing links are visible.
+Files: `lib/ui/screens/email_detail_screen.dart`.
+
+---
+
+## Group 4: User Experience
+
+### U1 — Done: https://codeberg.org/guettli/sharedinbox/pulls/26
+
+### U2 — Done: https://codeberg.org/guettli/sharedinbox/pulls/27
+
+### U3 🟡 Add "Recent searches" history to SearchScreen
+The search bar clears on navigation. Store the last 10 search terms in a local DB table and show them as chips below the search field when the field is focused but empty.
+Files: `lib/ui/screens/search_screen.dart`, `lib/data/db/database.dart`.
+
+### U4 — Done: https://codeberg.org/guettli/sharedinbox/pulls/28
+
+### U5 — Already implemented (Dismissible archive/delete swipes with undo, found in email_list_screen.dart)
+
+### U6 — Done: https://codeberg.org/guettli/sharedinbox/pulls/29
+
+### U7 🟢 Onboarding walkthrough for first-time users
+The app opens directly to an empty account list with only a `+` button. First-time users have no guidance.
+Add a one-time welcome card or bottom-sheet with the three-step flow: Add account → wait for sync → open inbox.
+Files: `lib/ui/screens/account_list_screen.dart`.
+
+### U8 🟢 "Mark all as read" action in mailbox
+Power users managing high-volume mailboxes need bulk read marking. Add a "Mark all as read" option in the mailbox overflow menu.
+Files: `lib/ui/screens/email_list_screen.dart`, `lib/core/repositories/email_repository.dart`, `lib/data/repositories/email_repository_impl.dart`.
+
+---
+
+## Group 5: Testing
+
+### T1 — Done: https://codeberg.org/guettli/sharedinbox/pulls/30
+
+### T2 — Done: https://codeberg.org/guettli/sharedinbox/pulls/31
+
+### T3 — Done: https://codeberg.org/guettli/sharedinbox/pulls/43
+
+### T3 🟡 Contract tests for all Repository interfaces
+The interfaces in `core/repositories/` have no shared contract test suite. Concrete impls can silently diverge.
+Add a shared `EmailRepositoryContract` abstract test class; run it against both `EmailRepositoryImpl` and any future mock/fake. Mirror this for `MailboxRepository` and `AccountRepository`.
+Files: `test/unit/` (new contract test files).
+
+### T4 — Done: https://codeberg.org/guettli/sharedinbox/pulls/32
+
+### T5 🟢 Snapshot / golden tests for key email list states
+The email list has multiple states: loading, empty, normal, selection mode, search active, error banner.
+Add golden tests using `matchesGoldenFile` for each state so visual regressions surface in CI.
+Files: `test/widget/email_list_screen_test.dart`.
+
+---
+
+## Group 6: Architecture & Code Quality
+
+### A1 — Done: https://codeberg.org/guettli/sharedinbox/pulls/39
+
+### A2 — Done: https://codeberg.org/guettli/sharedinbox/pulls/33
+
+### A3 — Done: https://codeberg.org/guettli/sharedinbox/pulls/46
+
+### A4 🟡 Replace raw JSON strings in DB with structured encoding
+`fromJson`, `toAddresses`, `ccJson`, `references` are stored as raw JSON strings parsed on every model conversion.
+Create typed value classes with `fromJson`/`toJson` in `core/models/email.dart` and add a `TypeConverter` in the Drift schema so the DB layer owns the serialisation.
+Files: `lib/data/db/database.dart`, `lib/core/models/email.dart`, `lib/data/repositories/email_repository_impl.dart`.
+
+### A5 🟢 Enforce layer boundaries via lint custom rules or barrel imports
+The `ui/` layer directly imports `data/` concrete classes in several screens (e.g. `drift` types leak through).
+Add a custom `analysis_options.yaml` rule or a CI lint step that flags any `ui/` import of `data/` (only `core/` interfaces are allowed from UI).
+Files: `analysis_options.yaml`, CI config.
+
+---
+
+## Group 7: Developer Experience
+
+### D1 🔴 CI matrix for macOS and Windows builds
+The CI currently tests Linux and Android. The macOS and Windows targets are "scaffolded" and may have accumulated silent breakage.
+Add `flutter build macos --debug` and `flutter build windows --debug` jobs to the CI workflow with the same failure threshold as Linux.
+Files: `.github/workflows/ci.yml` (or Codeberg equivalent).
+
+### D2 — Done: https://codeberg.org/guettli/sharedinbox/pulls/34
+
+### D3 🟢 Document the sync protocol in a SYNC.md architecture doc
+`DB-SYNC.md` exists but focuses on the DB schema. The IMAP IDLE loop, exponential backoff, pending-change queue, and undo cancel logic are spread across four files with no single reference.
+Write `SYNC.md` that describes the full lifecycle of an email action from UI tap to server confirmation.
+Files: `SYNC.md` (new).

pubspec.yaml

@@ -45,6 +45,10 @@ dependencies:
   url_launcher: ^6.3.2
   flutter_markdown: ^0.7.7+1
 
+  # Background sync and local notifications
+  flutter_local_notifications: ^18.0.1
+  workmanager: ^0.9.0
+
 dev_dependencies:
   flutter_test:
     sdk: flutter

scripts/check_coverage.dart

@@ -17,6 +17,7 @@ const _noCode = {
   'lib/core/repositories/mailbox_repository.dart',
   'lib/core/repositories/sync_log_repository.dart',
   'lib/core/repositories/undo_repository.dart',
+  'lib/core/repositories/search_history_repository.dart',
   'lib/core/models/undo_action.dart',
   'lib/core/storage/secure_storage.dart',
 };
@@ -52,6 +53,7 @@ const _excluded = {
   'lib/ui/widgets/try_connection_button.dart',
   'lib/ui/widgets/undo_shell.dart',
   'lib/core/sync/account_sync_manager.dart',
+  'lib/core/sync/background_sync.dart',
   'lib/core/sync/reliability_runner.dart',
   'lib/data/jmap/jmap_client.dart',
   'lib/data/jmap/sieve_repository.dart',
@@ -60,6 +62,7 @@ const _excluded = {
   'lib/data/repositories/mailbox_repository_impl.dart',
   'lib/data/repositories/sync_log_repository_impl.dart',
   'lib/data/repositories/undo_repository_impl.dart',
+  'lib/data/repositories/search_history_repository_impl.dart',
 };
 
 void main() {

scripts/deploy_playstore.py

@@ -4,7 +4,10 @@
 import json
 import os
 import sys
+import time
 
+import google_auth_httplib2
+import httplib2
 from google.oauth2 import service_account
 from googleapiclient.discovery import build
 from googleapiclient.http import MediaFileUpload
@@ -12,6 +15,15 @@ from googleapiclient.http import MediaFileUpload
 PACKAGE_NAME = "de.sharedinbox.mua"
 AAB_PATH = "build/app/outputs/bundle/release/app-release.aab"
 TRACK = "internal"
+_TIMEOUT = 300  # seconds — AAB uploads can be large
+_MAX_UPLOAD_ATTEMPTS = 3
+
+
+def _make_service(creds):
+    authorized_http = google_auth_httplib2.AuthorizedHttp(
+        creds, http=httplib2.Http(timeout=_TIMEOUT)
+    )
+    return build("androidpublisher", "v3", http=authorized_http)
 
 
 def main():
@@ -29,19 +41,43 @@ def main():
         scopes=["https://www.googleapis.com/auth/androidpublisher"],
     )
 
-    service = build("androidpublisher", "v3", credentials=creds)
+    service = _make_service(creds)
 
-    edit = service.edits().insert(body={}, packageName=PACKAGE_NAME).execute()
+    edit = service.edits().insert(body={}, packageName=PACKAGE_NAME).execute(num_retries=3)
     edit_id = edit["id"]
 
-    media = MediaFileUpload(AAB_PATH, mimetype="application/octet-stream", resumable=True)
-    bundle = (
-        service.edits()
-        .bundles()
-        .upload(packageName=PACKAGE_NAME, editId=edit_id, media_body=media)
-        .execute()
-    )
-    version_code = bundle["versionCode"]
+    # The resumable upload can fail with RedirectMissingLocation on transient
+    # network hiccups. Retry the upload (with a fresh MediaFileUpload each
+    # time) using exponential backoff before giving up.
+    version_code = None
+    last_exc = None
+    for attempt in range(_MAX_UPLOAD_ATTEMPTS):
+        try:
+            media = MediaFileUpload(
+                AAB_PATH, mimetype="application/octet-stream", resumable=True
+            )
+            bundle = (
+                service.edits()
+                .bundles()
+                .upload(packageName=PACKAGE_NAME, editId=edit_id, media_body=media)
+                .execute(num_retries=3)
+            )
+            version_code = bundle["versionCode"]
+            break
+        except httplib2.error.RedirectMissingLocation as exc:
+            last_exc = exc
+            if attempt < _MAX_UPLOAD_ATTEMPTS - 1:
+                delay = 10 * (2 ** attempt)
+                print(
+                    f"Upload attempt {attempt + 1} failed (redirect error), "
+                    f"retrying in {delay}s…"
+                )
+                time.sleep(delay)
+    else:
+        raise RuntimeError(
+            f"AAB upload failed after {_MAX_UPLOAD_ATTEMPTS} attempts"
+        ) from last_exc
+
     print(f"Uploaded AAB, version code: {version_code}")
 
     service.edits().tracks().update(
@@ -49,9 +85,9 @@ def main():
         editId=edit_id,
         track=TRACK,
         body={"releases": [{"versionCodes": [version_code], "status": "completed"}]},
-    ).execute()
+    ).execute(num_retries=3)
 
-    service.edits().commit(packageName=PACKAGE_NAME, editId=edit_id).execute()
+    service.edits().commit(packageName=PACKAGE_NAME, editId=edit_id).execute(num_retries=3)
     print(f"Deployed version {version_code} to {TRACK} track")
 
 

test/integration/account_sync_manager_test.dart

@@ -105,10 +105,19 @@ class _FakeEmails implements EmailRepository {
   final syncCounts = <String, int>{};
 
   @override
-  Stream<List<Email>> observeEmails(String a, String m) => Stream.value([]);
+  Stream<List<Email>> observeEmails(
+    String a,
+    String m, {
+    int limit = 50,
+  }) =>
+      Stream.value([]);
 
   @override
-  Stream<List<EmailThread>> observeThreads(String a, String m) =>
+  Stream<List<EmailThread>> observeThreads(
+    String a,
+    String m, {
+    int limit = 50,
+  }) =>
       Stream.value([]);
 
   @override

test/unit/account_repository_contract_test.dart

@@ -0,0 +1,107 @@
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:sharedinbox/core/models/account.dart';
+import 'package:sharedinbox/core/repositories/account_repository.dart';
+import 'package:sharedinbox/data/repositories/account_repository_impl.dart';
+
+import 'account_repository_impl_test.dart' show MapSecureStorage;
+import 'db_test_helper.dart';
+
+// ── Contract ──────────────────────────────────────────────────────────────────
+
+/// Verifies the [AccountRepository] interface contract.
+///
+/// Subclass this and override [makeRepo] to run the same suite against any
+/// concrete implementation.
+abstract class AccountRepositoryContract {
+  AccountRepository makeRepo();
+
+  static const _a = Account(
+    id: 'c-1',
+    displayName: 'Contract',
+    email: 'c@example.com',
+    imapHost: 'imap.example.com',
+    smtpHost: 'smtp.example.com',
+  );
+
+  void run() {
+    test('observeAccounts starts empty', () async {
+      final repo = makeRepo();
+      expect(await repo.observeAccounts().first, isEmpty);
+    });
+
+    test('addAccount makes account visible via observeAccounts', () async {
+      final repo = makeRepo();
+      await repo.addAccount(_a, 'pw');
+      final list = await repo.observeAccounts().first;
+      expect(list, hasLength(1));
+      expect(list.first.id, _a.id);
+    });
+
+    test('getAccount returns null for unknown id', () async {
+      final repo = makeRepo();
+      expect(await repo.getAccount('no-such'), isNull);
+    });
+
+    test('getAccount returns added account', () async {
+      final repo = makeRepo();
+      await repo.addAccount(_a, 'pw');
+      final a = await repo.getAccount(_a.id);
+      expect(a, isNotNull);
+      expect(a!.email, _a.email);
+    });
+
+    test('getPassword returns stored password', () async {
+      final repo = makeRepo();
+      await repo.addAccount(_a, 'secret123');
+      expect(await repo.getPassword(_a.id), 'secret123');
+    });
+
+    test('updateAccount reflects changes in observeAccounts', () async {
+      final repo = makeRepo();
+      await repo.addAccount(_a, 'pw');
+      final updated = _a.copyWith(displayName: 'Updated');
+      await repo.updateAccount(updated);
+      final list = await repo.observeAccounts().first;
+      expect(list.first.displayName, 'Updated');
+    });
+
+    test('updateAccount with password updates stored password', () async {
+      final repo = makeRepo();
+      await repo.addAccount(_a, 'old');
+      await repo.updateAccount(_a, password: 'new');
+      expect(await repo.getPassword(_a.id), 'new');
+    });
+
+    test('removeAccount makes account disappear from observeAccounts',
+        () async {
+      final repo = makeRepo();
+      await repo.addAccount(_a, 'pw');
+      await repo.removeAccount(_a.id);
+      expect(await repo.observeAccounts().first, isEmpty);
+    });
+
+    test('getAccount returns null after removeAccount', () async {
+      final repo = makeRepo();
+      await repo.addAccount(_a, 'pw');
+      await repo.removeAccount(_a.id);
+      expect(await repo.getAccount(_a.id), isNull);
+    });
+  }
+}
+
+// ── Impl under test ───────────────────────────────────────────────────────────
+
+class _AccountRepositoryImplContract extends AccountRepositoryContract {
+  @override
+  AccountRepository makeRepo() =>
+      AccountRepositoryImpl(openTestDatabase(), MapSecureStorage());
+}
+
+void main() {
+  setUpAll(configureSqliteForTests);
+
+  group('AccountRepositoryImpl satisfies AccountRepository contract', () {
+    _AccountRepositoryImplContract().run();
+  });
+}

test/unit/account_sync_manager_test.dart

@@ -34,9 +34,18 @@ void main() {
 
 class FakeEmailRepository implements EmailRepository {
   @override
-  Stream<List<Email>> observeEmails(String a, String m) => Stream.value([]);
+  Stream<List<Email>> observeEmails(
+    String a,
+    String m, {
+    int limit = 50,
+  }) =>
+      Stream.value([]);
   @override
-  Stream<List<EmailThread>> observeThreads(String a, String m) =>
+  Stream<List<EmailThread>> observeThreads(
+    String a,
+    String m, {
+    int limit = 50,
+  }) =>
       Stream.value([]);
   @override
   Stream<List<Email>> observeEmailsInThread(String a, String m, String t) =>

test/unit/account_sync_manager_test.mocks.dart

@@ -187,6 +187,16 @@ class MockMailboxRepository extends _i1.Mock implements _i7.MailboxRepository {
         ),
         returnValue: _i4.Future<_i8.Mailbox?>.value(),
       ) as _i4.Future<_i8.Mailbox?>);
+
+  @override
+  _i4.Future<void> clearForResync(String? accountId) => (super.noSuchMethod(
+        Invocation.method(
+          #clearForResync,
+          [accountId],
+        ),
+        returnValue: _i4.Future<void>.value(),
+        returnValueForMissingStub: _i4.Future<void>.value(),
+      ) as _i4.Future<void>);
 }
 
 /// A class which mocks [EmailRepository].
@@ -206,8 +216,9 @@ class MockEmailRepository extends _i1.Mock implements _i9.EmailRepository {
   @override
   _i4.Stream<List<_i2.Email>> observeEmails(
     String? accountId,
-    String? mailboxPath,
-  ) =>
+    String? mailboxPath, {
+    int? limit = 50,
+  }) =>
       (super.noSuchMethod(
         Invocation.method(
           #observeEmails,
@@ -215,6 +226,7 @@ class MockEmailRepository extends _i1.Mock implements _i9.EmailRepository {
             accountId,
             mailboxPath,
           ],
+          {#limit: limit},
         ),
         returnValue: _i4.Stream<List<_i2.Email>>.empty(),
       ) as _i4.Stream<List<_i2.Email>>);
@@ -222,8 +234,9 @@ class MockEmailRepository extends _i1.Mock implements _i9.EmailRepository {
   @override
   _i4.Stream<List<_i2.EmailThread>> observeThreads(
     String? accountId,
-    String? mailboxPath,
-  ) =>
+    String? mailboxPath, {
+    int? limit = 50,
+  }) =>
       (super.noSuchMethod(
         Invocation.method(
           #observeThreads,
@@ -231,6 +244,7 @@ class MockEmailRepository extends _i1.Mock implements _i9.EmailRepository {
             accountId,
             mailboxPath,
           ],
+          {#limit: limit},
         ),
         returnValue: _i4.Stream<List<_i2.EmailThread>>.empty(),
       ) as _i4.Stream<List<_i2.EmailThread>>);
@@ -582,4 +596,14 @@ class MockEmailRepository extends _i1.Mock implements _i9.EmailRepository {
           ),
         )),
       ) as _i4.Future<_i2.ReliabilityResult>);
+
+  @override
+  _i4.Future<void> clearForResync(String? accountId) => (super.noSuchMethod(
+        Invocation.method(
+          #clearForResync,
+          [accountId],
+        ),
+        returnValue: _i4.Future<void>.value(),
+        returnValueForMissingStub: _i4.Future<void>.value(),
+      ) as _i4.Future<void>);
 }

test/unit/draft_repository_impl_test.dart

@@ -1,9 +1,25 @@
 import 'package:flutter_test/flutter_test.dart';
-
+import 'package:sharedinbox/core/models/account.dart';
+import 'package:sharedinbox/core/repositories/account_repository.dart';
 import 'package:sharedinbox/data/repositories/draft_repository_impl.dart';
 
 import 'db_test_helper.dart';
 
+class _StubAccounts implements AccountRepository {
+  @override
+  Stream<List<Account>> observeAccounts() => const Stream.empty();
+  @override
+  Future<Account?> getAccount(String id) async => null;
+  @override
+  Future<void> addAccount(Account account, String password) async {}
+  @override
+  Future<void> updateAccount(Account account, {String? password}) async {}
+  @override
+  Future<void> removeAccount(String id) async {}
+  @override
+  Future<String> getPassword(String accountId) async => '';
+}
+
 void main() {
   setUpAll(configureSqliteForTests);
 
@@ -11,7 +27,7 @@ void main() {
     test(
       'saveDraft creates a new row and returns it with a non-zero id',
       () async {
-        final repo = DraftRepositoryImpl(openTestDatabase());
+        final repo = DraftRepositoryImpl(openTestDatabase(), _StubAccounts());
         final draft = await repo.saveDraft(
           toText: 'bob@example.com',
           ccText: '',
@@ -25,7 +41,7 @@ void main() {
     );
 
     test('saveDraft with id updates existing row', () async {
-      final repo = DraftRepositoryImpl(openTestDatabase());
+      final repo = DraftRepositoryImpl(openTestDatabase(), _StubAccounts());
       final created = await repo.saveDraft(
         toText: 'a@example.com',
         ccText: '',
@@ -47,19 +63,19 @@ void main() {
     });
 
     test('getDraft returns null for unknown id', () async {
-      final repo = DraftRepositoryImpl(openTestDatabase());
+      final repo = DraftRepositoryImpl(openTestDatabase(), _StubAccounts());
       expect(await repo.getDraft(99999), isNull);
     });
 
     test('findDraft returns null when no draft exists', () async {
-      final repo = DraftRepositoryImpl(openTestDatabase());
+      final repo = DraftRepositoryImpl(openTestDatabase(), _StubAccounts());
       expect(await repo.findDraft(), isNull);
     });
 
     test(
       'findDraft returns most recent draft for matching replyToEmailId',
       () async {
-        final repo = DraftRepositoryImpl(openTestDatabase());
+        final repo = DraftRepositoryImpl(openTestDatabase(), _StubAccounts());
         await repo.saveDraft(
           replyToEmailId: 'email-1',
           toText: 'a@example.com',
@@ -83,7 +99,7 @@ void main() {
     test(
       'findDraft with null replyToEmailId finds new-message drafts',
       () async {
-        final repo = DraftRepositoryImpl(openTestDatabase());
+        final repo = DraftRepositoryImpl(openTestDatabase(), _StubAccounts());
         // This draft is a reply and should NOT be returned.
         await repo.saveDraft(
           replyToEmailId: 'email-1',
@@ -104,7 +120,7 @@ void main() {
     );
 
     test('deleteDraft removes the row', () async {
-      final repo = DraftRepositoryImpl(openTestDatabase());
+      final repo = DraftRepositoryImpl(openTestDatabase(), _StubAccounts());
       final draft = await repo.saveDraft(
         toText: 'a@example.com',
         ccText: '',

test/unit/email_repository_contract_test.dart

@@ -0,0 +1,193 @@
+import 'package:drift/drift.dart' show Value;
+import 'package:enough_mail/enough_mail.dart' as imap;
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:sharedinbox/core/models/account.dart';
+import 'package:sharedinbox/core/repositories/email_repository.dart';
+import 'package:sharedinbox/data/db/database.dart' hide Account;
+import 'package:sharedinbox/data/repositories/account_repository_impl.dart';
+import 'package:sharedinbox/data/repositories/email_repository_impl.dart';
+
+import 'account_repository_impl_test.dart' show MapSecureStorage;
+import 'db_test_helper.dart';
+
+// ── Contract ──────────────────────────────────────────────────────────────────
+
+/// Verifies the observable / local-state portion of the [EmailRepository]
+/// interface contract.
+///
+/// Network-dependent methods (syncEmails, sendEmail, etc.) are intentionally
+/// excluded — they are covered by the concrete impl tests.
+abstract class EmailRepositoryContract {
+  static const _account = Account(
+    id: 'er-acc',
+    displayName: 'Contract',
+    email: 'er@example.com',
+    imapHost: 'imap.example.com',
+    smtpHost: 'smtp.example.com',
+  );
+
+  /// Return a fresh [EmailRepository] with [_account] already persisted.
+  Future<EmailRepository> makeRepo();
+
+  /// Insert a raw email row so tests can assert on observable state without
+  /// triggering a network sync.
+  Future<void> insertEmail(
+    EmailRepository repo, {
+    required String id,
+    required String mailboxPath,
+    bool isSeen = true,
+    bool isFlagged = false,
+    DateTime? receivedAt,
+  });
+
+  void run() {
+    test('observeEmails starts empty', () async {
+      final repo = await makeRepo();
+      expect(
+        await repo.observeEmails(_account.id, 'INBOX').first,
+        isEmpty,
+      );
+    });
+
+    test('observeEmails emits inserted email', () async {
+      final repo = await makeRepo();
+      await insertEmail(repo, id: 'er-acc:1', mailboxPath: 'INBOX');
+      final emails = await repo.observeEmails(_account.id, 'INBOX').first;
+      expect(emails, hasLength(1));
+      expect(emails.first.id, 'er-acc:1');
+    });
+
+    test('observeEmails only returns emails for the given mailbox', () async {
+      final repo = await makeRepo();
+      await insertEmail(repo, id: 'er-acc:1', mailboxPath: 'INBOX');
+      expect(
+        await repo.observeEmails(_account.id, 'Sent').first,
+        isEmpty,
+      );
+    });
+
+    test('observeEmails orders by receivedAt descending', () async {
+      final repo = await makeRepo();
+      final older = DateTime(2024);
+      final newer = DateTime(2024, 6);
+      await insertEmail(
+        repo,
+        id: 'er-acc:1',
+        mailboxPath: 'INBOX',
+        receivedAt: older,
+      );
+      await insertEmail(
+        repo,
+        id: 'er-acc:2',
+        mailboxPath: 'INBOX',
+        receivedAt: newer,
+      );
+      final emails = await repo.observeEmails(_account.id, 'INBOX').first;
+      expect(emails.first.id, 'er-acc:2');
+      expect(emails.last.id, 'er-acc:1');
+    });
+
+    test('getEmail returns null for unknown id', () async {
+      final repo = await makeRepo();
+      expect(await repo.getEmail('no-such'), isNull);
+    });
+
+    test('getEmail returns inserted email', () async {
+      final repo = await makeRepo();
+      await insertEmail(repo, id: 'er-acc:7', mailboxPath: 'INBOX');
+      final email = await repo.getEmail('er-acc:7');
+      expect(email, isNotNull);
+      expect(email!.accountId, _account.id);
+    });
+
+    test('setFlag seen updates isSeen', () async {
+      final repo = await makeRepo();
+      await insertEmail(
+        repo,
+        id: 'er-acc:10',
+        mailboxPath: 'INBOX',
+        isSeen: false,
+      );
+      await repo.setFlag('er-acc:10', seen: true);
+      final email = await repo.getEmail('er-acc:10');
+      expect(email!.isSeen, isTrue);
+    });
+
+    test('setFlag flagged updates isFlagged', () async {
+      final repo = await makeRepo();
+      await insertEmail(
+        repo,
+        id: 'er-acc:11',
+        mailboxPath: 'INBOX',
+      );
+      await repo.setFlag('er-acc:11', flagged: true);
+      final email = await repo.getEmail('er-acc:11');
+      expect(email!.isFlagged, isTrue);
+    });
+
+    test('observeThreads starts empty', () async {
+      final repo = await makeRepo();
+      expect(
+        await repo.observeThreads(_account.id, 'INBOX').first,
+        isEmpty,
+      );
+    });
+  }
+}
+
+// ── Impl under test ───────────────────────────────────────────────────────────
+
+class _EmailRepositoryImplContract extends EmailRepositoryContract {
+  static const _account = EmailRepositoryContract._account;
+
+  late AppDatabase _db;
+  late AccountRepositoryImpl _accountRepo;
+
+  @override
+  Future<EmailRepository> makeRepo() async {
+    _db = openTestDatabase();
+    _accountRepo = AccountRepositoryImpl(_db, MapSecureStorage());
+    await _accountRepo.addAccount(_account, 'pw');
+    return EmailRepositoryImpl(
+      _db,
+      _accountRepo,
+      imapConnect: (_, __, ___) => Future<imap.ImapClient>.error(
+        UnsupportedError('no IMAP in unit tests'),
+      ),
+      smtpConnect: (_, __, ___) => Future<imap.SmtpClient>.error(
+        UnsupportedError('no SMTP in unit tests'),
+      ),
+    );
+  }
+
+  @override
+  Future<void> insertEmail(
+    EmailRepository repo, {
+    required String id,
+    required String mailboxPath,
+    bool isSeen = true,
+    bool isFlagged = false,
+    DateTime? receivedAt,
+  }) async {
+    await _db.into(_db.emails).insert(
+          EmailsCompanion.insert(
+            id: id,
+            accountId: _account.id,
+            mailboxPath: mailboxPath,
+            uid: int.parse(id.split(':').last),
+            receivedAt: receivedAt ?? DateTime.now(),
+            isSeen: Value(isSeen),
+            isFlagged: Value(isFlagged),
+          ),
+        );
+  }
+}
+
+void main() {
+  setUpAll(configureSqliteForTests);
+
+  group('EmailRepositoryImpl satisfies EmailRepository contract', () {
+    _EmailRepositoryImplContract().run();
+  });
+}

test/unit/email_repository_impl_test.dart

@@ -1,7 +1,7 @@
 import 'dart:async';
 import 'dart:convert';
 
-import 'package:drift/drift.dart' show Value;
+import 'package:drift/drift.dart' hide isNull, isNotNull;
 import 'package:enough_mail/enough_mail.dart' as imap;
 import 'package:flutter_test/flutter_test.dart';
 import 'package:http/http.dart' as http;
@@ -16,6 +16,7 @@ import 'package:sharedinbox/data/repositories/email_repository_impl.dart';
 
 import 'account_repository_impl_test.dart' show MapSecureStorage;
 import 'db_test_helper.dart';
+import 'fake_imap.dart' show FakeImapClient;
 // ── Helpers ───────────────────────────────────────────────────────────────────
 
 const _account = Account(
@@ -162,15 +163,19 @@ Future<imap.SmtpClient> _noSmtpConnect(Account a, String u, String p) =>
     Future.error(UnsupportedError('SMTP unavailable in unit tests'));
 
 ({AppDatabase db, AccountRepositoryImpl accounts, EmailRepositoryImpl emails})
-    _makeRepos({http.Client? httpClient}) {
+    _makeRepos({
+  http.Client? httpClient,
+  Future<imap.ImapClient> Function(Account, String, String)? imapConnect,
+  Future<imap.SmtpClient> Function(Account, String, String)? smtpConnect,
+}) {
   final db = openTestDatabase();
   final storage = MapSecureStorage();
   final accounts = AccountRepositoryImpl(db, storage);
   final emails = EmailRepositoryImpl(
     db,
     accounts,
-    imapConnect: _noImapConnect,
-    smtpConnect: _noSmtpConnect,
+    imapConnect: imapConnect ?? _noImapConnect,
+    smtpConnect: smtpConnect ?? _noSmtpConnect,
     httpClient: httpClient,
   );
   return (db: db, accounts: accounts, emails: emails);
@@ -1935,6 +1940,163 @@ void main() {
       expect(row.lastError, isNull);
     });
   });
+
+  group('concurrent moves', () {
+    test(
+        'two simultaneous moves enqueue two changes and leave email in last destination',
+        () async {
+      final r = _makeRepos();
+      await r.accounts.addAccount(_account, 'pw');
+      await r.db.into(r.db.emails).insert(
+            EmailsCompanion.insert(
+              id: 'acc-1:5',
+              accountId: 'acc-1',
+              mailboxPath: 'INBOX',
+              uid: 5,
+              receivedAt: DateTime(2024),
+            ),
+          );
+
+      // Fire both moves without awaiting to exercise concurrent enqueue logic.
+      final f1 = r.emails.moveEmail('acc-1:5', 'Archive');
+      final f2 = r.emails.moveEmail('acc-1:5', 'Trash');
+      await Future.wait([f1, f2]);
+
+      final changes = await r.db.select(r.db.pendingChanges).get();
+      expect(changes, hasLength(2));
+      expect(changes.map((c) => c.changeType), everyElement('move'));
+
+      final destinations =
+          changes.map((c) => (jsonDecode(c.payload) as Map)['dest']).toSet();
+      expect(destinations, containsAll(['Archive', 'Trash']));
+
+      final email = await r.emails.getEmail('acc-1:5');
+      expect(
+        email!.mailboxPath,
+        anyOf('Archive', 'Trash'),
+        reason:
+            'email must be optimistically moved to one of the two destinations',
+      );
+    });
+  });
+
+  group('IMAP SMTP auth failure', () {
+    test('sendEmail propagates SMTP authentication error', () async {
+      final r = _makeRepos(
+        smtpConnect: (Account _, String __, String ___) => Future.error(
+          Exception('535 5.7.8 Authentication credentials invalid'),
+        ),
+      );
+      await r.accounts.addAccount(_account, 'pw');
+
+      const draft = EmailDraft(
+        from: EmailAddress(name: 'Alice', email: 'alice@example.com'),
+        to: [EmailAddress(name: 'Bob', email: 'bob@example.com')],
+        cc: [],
+        subject: 'Test',
+        body: 'Body',
+      );
+
+      await expectLater(
+        r.emails.sendEmail('acc-1', draft),
+        throwsA(
+          isA<Exception>().having(
+            (e) => e.toString(),
+            'message',
+            contains('535'),
+          ),
+        ),
+      );
+    });
+  });
+
+  group('IMAP UID validity change', () {
+    test('full re-sync wipes stale emails when uidValidity changes', () async {
+      final r = _makeRepos(
+        imapConnect: (Account _, String __, String ___) async =>
+            _FakeImapClientUidValidity(456),
+      );
+      await r.accounts.addAccount(_account, 'pw');
+
+      // Pre-seed two emails from the old server epoch (uidValidity=123).
+      await r.db.into(r.db.emails).insert(
+            EmailsCompanion.insert(
+              id: 'acc-1:1',
+              accountId: 'acc-1',
+              mailboxPath: 'INBOX',
+              uid: 1,
+              receivedAt: DateTime(2024),
+            ),
+          );
+      await r.db.into(r.db.emails).insert(
+            EmailsCompanion.insert(
+              id: 'acc-1:2',
+              accountId: 'acc-1',
+              mailboxPath: 'INBOX',
+              uid: 2,
+              receivedAt: DateTime(2024),
+            ),
+          );
+
+      // Seed an IMAP checkpoint with the old uidValidity so the code detects
+      // a mismatch and triggers a full re-sync.
+      await r.db.into(r.db.syncStates).insertOnConflictUpdate(
+            SyncStatesCompanion.insert(
+              accountId: 'acc-1',
+              resourceType: 'IMAP:INBOX',
+              state: '{"uidValidity":123,"lastUid":2,"highestModSeq":null}',
+              syncedAt: DateTime(2024),
+            ),
+          );
+
+      await r.emails.syncEmails('acc-1', 'INBOX');
+
+      // Old emails must be wiped; the fake server returns zero messages.
+      final remaining = await r.db.select(r.db.emails).get();
+      expect(remaining, isEmpty);
+
+      // Checkpoint must be updated to the new uidValidity.
+      final stateRow = await (r.db.select(r.db.syncStates)
+            ..where(
+              (t) =>
+                  t.accountId.equals('acc-1') &
+                  t.resourceType.equals('IMAP:INBOX'),
+            ))
+          .getSingleOrNull();
+      expect(stateRow, isNotNull);
+      final state = jsonDecode(stateRow!.state) as Map<String, dynamic>;
+      expect(state['uidValidity'], 456);
+    });
+  });
+}
+
+// ── Additional fake IMAP client for UID-validity tests ───────────────────────
+
+class _FakeImapClientUidValidity extends FakeImapClient {
+  _FakeImapClientUidValidity(this._uidValidity);
+  final int _uidValidity;
+
+  @override
+  Future<imap.Mailbox> selectMailboxByPath(
+    String path, {
+    bool enableCondStore = false,
+    imap.QResyncParameters? qresync,
+  }) async =>
+      imap.Mailbox(
+        encodedName: path,
+        encodedPath: path,
+        flags: [],
+        pathSeparator: '/',
+        uidValidity: _uidValidity,
+      );
+
+  @override
+  Future<imap.SearchImapResult> uidSearchMessages({
+    String searchCriteria = 'ALL',
+    List<imap.ReturnOption>? returnOptions,
+    Duration? responseTimeout,
+  }) async =>
+      imap.SearchImapResult();
 }
 
 // ── SSE test helper ──────────────────────────────────────────────────────────

test/unit/mailbox_repository_contract_test.dart

@@ -0,0 +1,137 @@
+import 'package:drift/drift.dart' show Value;
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:sharedinbox/core/models/account.dart';
+import 'package:sharedinbox/core/repositories/mailbox_repository.dart';
+import 'package:sharedinbox/data/db/database.dart' hide Account;
+import 'package:sharedinbox/data/repositories/account_repository_impl.dart';
+import 'package:sharedinbox/data/repositories/mailbox_repository_impl.dart';
+
+import 'account_repository_impl_test.dart' show MapSecureStorage;
+import 'db_test_helper.dart';
+
+// ── Contract ──────────────────────────────────────────────────────────────────
+
+/// Verifies the [MailboxRepository] interface contract.
+///
+/// Tests cover only the locally-observable part of the interface
+/// (observe / find) since sync methods require live IMAP/JMAP servers.
+abstract class MailboxRepositoryContract {
+  static const _account = Account(
+    id: 'm-acc',
+    displayName: 'Contract',
+    email: 'm@example.com',
+    imapHost: 'imap.example.com',
+    smtpHost: 'smtp.example.com',
+  );
+
+  /// Return a fresh [MailboxRepository] with [_account] already persisted.
+  Future<MailboxRepository> makeRepo();
+
+  /// Insert a mailbox row into the backing store so tests can verify
+  /// observeMailboxes without triggering a network sync.
+  Future<void> insertMailbox(
+    MailboxRepository repo, {
+    required String id,
+    required String path,
+    String? role,
+    int unread = 0,
+    int total = 0,
+  });
+
+  void run() {
+    test('observeMailboxes starts empty', () async {
+      final repo = await makeRepo();
+      expect(await repo.observeMailboxes(_account.id).first, isEmpty);
+    });
+
+    test('observeMailboxes emits inserted rows ordered by path', () async {
+      final repo = await makeRepo();
+      await insertMailbox(repo, id: 'z', path: 'Z');
+      await insertMailbox(repo, id: 'a', path: 'A');
+      final boxes = await repo.observeMailboxes(_account.id).first;
+      expect(boxes.map((b) => b.path), ['A', 'Z']);
+    });
+
+    test('observeMailboxes only returns rows for the given account', () async {
+      final repo = await makeRepo();
+      await insertMailbox(repo, id: 'mb1', path: 'INBOX');
+      expect(await repo.observeMailboxes('other-acc').first, isEmpty);
+    });
+
+    test('findMailboxByRole returns null when no match', () async {
+      final repo = await makeRepo();
+      expect(
+        await repo.findMailboxByRole(_account.id, 'archive'),
+        isNull,
+      );
+    });
+
+    test('findMailboxByRole returns the matching mailbox', () async {
+      final repo = await makeRepo();
+      await insertMailbox(repo, id: 'arch', path: 'Archive', role: 'archive');
+      final box = await repo.findMailboxByRole(_account.id, 'archive');
+      expect(box, isNotNull);
+      expect(box!.role, 'archive');
+    });
+
+    test('clearForResync removes all mailboxes for the account', () async {
+      final repo = await makeRepo();
+      await insertMailbox(repo, id: 'mb', path: 'INBOX');
+      await repo.clearForResync(_account.id);
+      expect(await repo.observeMailboxes(_account.id).first, isEmpty);
+    });
+  }
+}
+
+// ── Impl under test ───────────────────────────────────────────────────────────
+
+class _MailboxRepositoryImplContract extends MailboxRepositoryContract {
+  static const _account = MailboxRepositoryContract._account;
+
+  late AppDatabase _db;
+  late AccountRepositoryImpl _accountRepo;
+
+  @override
+  Future<MailboxRepository> makeRepo() async {
+    _db = openTestDatabase();
+    _accountRepo = AccountRepositoryImpl(_db, MapSecureStorage());
+    await _accountRepo.addAccount(_account, 'pw');
+    return MailboxRepositoryImpl(
+      _db,
+      _accountRepo,
+      imapConnect: (_, __, ___) =>
+          Future.error(UnsupportedError('no IMAP in unit tests')),
+    );
+  }
+
+  @override
+  Future<void> insertMailbox(
+    MailboxRepository repo, {
+    required String id,
+    required String path,
+    String? role,
+    int unread = 0,
+    int total = 0,
+  }) async {
+    await _db.into(_db.mailboxes).insert(
+          MailboxesCompanion.insert(
+            id: id,
+            accountId: _account.id,
+            path: path,
+            name: path.split('/').last,
+            unreadCount: Value(unread),
+            totalCount: Value(total),
+            role: Value(role),
+          ),
+        );
+  }
+}
+
+void main() {
+  setUpAll(configureSqliteForTests);
+
+  group('MailboxRepositoryImpl satisfies MailboxRepository contract', () {
+    _MailboxRepositoryImplContract().run();
+  });
+}

test/unit/migration_test.dart

@@ -4,11 +4,22 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:sharedinbox/data/db/database.dart';
 import 'package:sqlite3/sqlite3.dart' as sqlite;
 
+/// Reads all column names for [tableName] from [db].
+Future<List<String>> _tableColumns(AppDatabase db, String tableName) async {
+  final rows = await db.customSelect('PRAGMA table_info($tableName)').get();
+  return rows.map((r) => r.read<String>('name')).toList();
+}
+
 void main() {
   group('Migration', () {
-    test('upgrade from v1 to latest', () async {
-      // 1. Create a V1 database using raw sqlite3.
-      final dbFile = File('test_migration.db');
+    test('schemaVersion matches expected value', () async {
+      final db = AppDatabase(NativeDatabase.memory());
+      expect(db.schemaVersion, 27);
+      await db.close();
+    });
+
+    test('upgrade from v1 to latest checks all added columns', () async {
+      final dbFile = File('test_migration_v1.db');
       if (dbFile.existsSync()) dbFile.deleteSync();
 
       final rawDb = sqlite.sqlite3.open(dbFile.path);
@@ -67,41 +78,276 @@ void main() {
       rawDb.execute('PRAGMA user_version = 1;');
       rawDb.close();
 
-      // 2. Open it with AppDatabase (v22).
       final db = AppDatabase(NativeDatabase(dbFile));
 
-      // Trigger migration by performing a simple query.
+      // Trigger migration by performing a query.
       final accs = await db.select(db.accounts).get();
       expect(accs, hasLength(1));
       expect(accs.first.displayName, 'Alice');
-      expect(accs.first.accountType, 'imap'); // default value
+      expect(accs.first.accountType, 'imap');
 
-      // 3. Verify that all columns exist.
-      // If migration failed, it would have thrown an exception during opening or query.
-      final tableInfo =
-          await db.customSelect('PRAGMA table_info(emails)').get();
-      final columns = tableInfo.map((r) => r.read<String>('name')).toList();
-
-      expect(columns, contains('thread_id'));
-      expect(columns, contains('snoozed_until'));
-      expect(columns, contains('snoozed_from_mailbox_path'));
-
-      final accountsInfo =
-          await db.customSelect('PRAGMA table_info(accounts)').get();
-      final accountColumns =
-          accountsInfo.map((r) => r.read<String>('name')).toList();
-      expect(accountColumns, contains('account_type'));
-      expect(accountColumns, contains('username'));
+      // v2–v3: accounts columns.
+      final accountColumns = await _tableColumns(db, 'accounts');
+      expect(
+        accountColumns,
+        containsAll(['account_type', 'jmap_url', 'username']),
+      );
       expect(accountColumns, contains('manage_sieve_host'));
 
+      // v14: threading columns.
+      final emailColumns = await _tableColumns(db, 'emails');
+      expect(
+        emailColumns,
+        containsAll(['thread_id', 'message_id', 'in_reply_to', 'references']),
+      );
+
+      // v22: snooze columns.
+      expect(
+        emailColumns,
+        containsAll(['snoozed_until', 'snoozed_from_mailbox_path']),
+      );
+
+      // v23: list-unsubscribe header column.
+      expect(emailColumns, contains('list_unsubscribe_header'));
+
+      // v8: mailboxes role column.
+      final mailboxColumns = await _tableColumns(db, 'mailboxes');
+      expect(mailboxColumns, contains('role'));
+
+      // v9: email_bodies cached_at column.
+      final bodyColumns = await _tableColumns(db, 'email_bodies');
+      expect(bodyColumns, contains('cached_at'));
+      expect(bodyColumns, contains('headers_json'));
+
+      // v4: drafts table with v24 imap_server_id column.
+      final draftColumns = await _tableColumns(db, 'drafts');
+      expect(draftColumns, contains('imap_server_id'));
+
+      // v5, v6, v7, v12, v17, v19, v21: new tables.
+      final allTables = await db
+          .customSelect("SELECT name FROM sqlite_master WHERE type='table'")
+          .get();
+      final tableNames = allTables.map((r) => r.read<String>('name')).toList();
+      expect(
+        tableNames,
+        containsAll([
+          'sync_states', // v5
+          'pending_changes', // v6
+          'sync_logs', // v7
+          'sync_log_mailboxes', // v12
+          'threads', // v17
+          'sync_health', // v19
+          'undo_actions', // v21
+        ]),
+      );
+
+      // v18, v22, v25: indexes.
+      final allIndexes = await db
+          .customSelect("SELECT name FROM sqlite_master WHERE type='index'")
+          .get();
+      final indexNames = allIndexes.map((r) => r.read<String>('name')).toSet();
+      expect(
+        indexNames,
+        containsAll([
+          'emails_received_at', // v18
+          'emails_thread_id', // v18
+          'pending_changes_account_id', // v18
+          'emails_snoozed_until', // v22
+          'mailboxes_account_id', // v25
+          'threads_latest_date', // v25
+        ]),
+      );
+
+      // v26: FTS5 virtual table and triggers exist.
+      final allTriggers = await db
+          .customSelect("SELECT name FROM sqlite_master WHERE type='trigger'")
+          .get();
+      final triggerNames =
+          allTriggers.map((r) => r.read<String>('name')).toSet();
+      expect(
+        triggerNames,
+        containsAll(['email_fts_ai', 'email_fts_au', 'email_fts_ad']),
+      );
+      // Verify FTS table was created and is queryable.
+      await db.customSelect('SELECT count(*) FROM email_fts').get();
+
+      // v27: search_history_entries table.
+      await db
+          .customSelect('SELECT count(*) FROM search_history_entries')
+          .get();
+
       await db.close();
       if (dbFile.existsSync()) dbFile.deleteSync();
     });
 
-    test('fresh install (v22) works', () async {
-      final db = AppDatabase(NativeDatabase.memory());
-      // Just ensure we can create everything and query.
+    test(
+        'upgrade from v22 to latest adds list_unsubscribe_header and imap_server_id',
+        () async {
+      final dbFile = File('test_migration_v22.db');
+      if (dbFile.existsSync()) dbFile.deleteSync();
+
+      // Build a v22 database schema directly with raw SQL.
+      final rawDb = sqlite.sqlite3.open(dbFile.path);
+      rawDb.execute('''
+        CREATE TABLE accounts (
+          id TEXT NOT NULL PRIMARY KEY,
+          display_name TEXT NOT NULL,
+          email TEXT NOT NULL,
+          imap_host TEXT NOT NULL,
+          imap_port INTEGER NOT NULL DEFAULT 993,
+          imap_ssl INTEGER NOT NULL DEFAULT 1 CHECK ("imap_ssl" IN (0, 1)),
+          smtp_host TEXT NOT NULL DEFAULT '',
+          smtp_port INTEGER NOT NULL DEFAULT 465,
+          smtp_ssl INTEGER NOT NULL DEFAULT 1 CHECK ("smtp_ssl" IN (0, 1)),
+          account_type TEXT NOT NULL DEFAULT 'imap',
+          jmap_url TEXT NULL,
+          username TEXT NULL,
+          manage_sieve_host TEXT NULL,
+          manage_sieve_port INTEGER NULL,
+          manage_sieve_ssl INTEGER NULL,
+          manage_sieve_available INTEGER NOT NULL DEFAULT 0 CHECK ("manage_sieve_available" IN (0, 1)),
+          verbose INTEGER NOT NULL DEFAULT 0 CHECK ("verbose" IN (0, 1))
+        );
+      ''');
+      rawDb.execute('''
+        CREATE TABLE drafts (
+          id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
+          account_id TEXT NULL,
+          reply_to_email_id TEXT NULL,
+          to_text TEXT NOT NULL DEFAULT '',
+          cc_text TEXT NOT NULL DEFAULT '',
+          subject_text TEXT NOT NULL DEFAULT '',
+          body_text TEXT NOT NULL DEFAULT '',
+          updated_at INTEGER NOT NULL
+        );
+      ''');
+      rawDb.execute('''
+        CREATE TABLE mailboxes (
+          id TEXT NOT NULL PRIMARY KEY,
+          account_id TEXT NOT NULL,
+          path TEXT NOT NULL,
+          name TEXT NOT NULL,
+          unread_count INTEGER NOT NULL DEFAULT 0,
+          total_count INTEGER NOT NULL DEFAULT 0,
+          role TEXT NULL
+        );
+      ''');
+      rawDb.execute('''
+        CREATE TABLE emails (
+          id TEXT NOT NULL PRIMARY KEY,
+          account_id TEXT NOT NULL,
+          mailbox_path TEXT NOT NULL,
+          uid INTEGER NOT NULL,
+          subject TEXT NULL,
+          sent_at INTEGER NULL,
+          received_at INTEGER NOT NULL,
+          from_json TEXT NOT NULL DEFAULT '[]',
+          to_addresses TEXT NOT NULL DEFAULT '[]',
+          cc_json TEXT NOT NULL DEFAULT '[]',
+          preview TEXT NULL,
+          is_seen INTEGER NOT NULL DEFAULT 0 CHECK ("is_seen" IN (0, 1)),
+          is_flagged INTEGER NOT NULL DEFAULT 0 CHECK ("is_flagged" IN (0, 1)),
+          has_attachment INTEGER NOT NULL DEFAULT 0 CHECK ("has_attachment" IN (0, 1)),
+          thread_id TEXT NULL,
+          message_id TEXT NULL,
+          in_reply_to TEXT NULL,
+          "references" TEXT NULL,
+          snoozed_until INTEGER NULL,
+          snoozed_from_mailbox_path TEXT NULL
+        );
+      ''');
+      rawDb.execute('''
+        CREATE TABLE threads (
+          account_id TEXT NOT NULL,
+          mailbox_path TEXT NOT NULL,
+          id TEXT NOT NULL,
+          subject TEXT NULL,
+          latest_date INTEGER NOT NULL,
+          message_count INTEGER NOT NULL DEFAULT 1,
+          has_unread INTEGER NOT NULL DEFAULT 0 CHECK ("has_unread" IN (0, 1)),
+          is_flagged INTEGER NOT NULL DEFAULT 0 CHECK ("is_flagged" IN (0, 1)),
+          participants_json TEXT NOT NULL DEFAULT '[]',
+          preview TEXT NULL,
+          latest_email_id TEXT NOT NULL,
+          email_ids_json TEXT NOT NULL DEFAULT '[]',
+          PRIMARY KEY (account_id, mailbox_path, id)
+        );
+      ''');
+      rawDb.execute('PRAGMA user_version = 22;');
+      rawDb.close();
+
+      final db = AppDatabase(NativeDatabase(dbFile));
+      // Trigger migration.
       await db.select(db.accounts).get();
+
+      final emailColumns = await _tableColumns(db, 'emails');
+      expect(emailColumns, contains('list_unsubscribe_header'));
+
+      final draftColumns = await _tableColumns(db, 'drafts');
+      expect(draftColumns, contains('imap_server_id'));
+
+      // v25: new indexes on mailboxes and threads.
+      final allIndexes = await db
+          .customSelect("SELECT name FROM sqlite_master WHERE type='index'")
+          .get();
+      final indexNames = allIndexes.map((r) => r.read<String>('name')).toSet();
+      expect(indexNames, contains('mailboxes_account_id'));
+      expect(indexNames, contains('threads_latest_date'));
+
+      // v26: FTS5 virtual table and triggers.
+      final allTriggers = await db
+          .customSelect("SELECT name FROM sqlite_master WHERE type='trigger'")
+          .get();
+      final triggerNames =
+          allTriggers.map((r) => r.read<String>('name')).toSet();
+      expect(
+        triggerNames,
+        containsAll(['email_fts_ai', 'email_fts_au', 'email_fts_ad']),
+      );
+      await db.customSelect('SELECT count(*) FROM email_fts').get();
+
+      // v27: search_history_entries table.
+      await db
+          .customSelect('SELECT count(*) FROM search_history_entries')
+          .get();
+
+      await db.close();
+      if (dbFile.existsSync()) dbFile.deleteSync();
+    });
+
+    test('fresh install creates all tables at schemaVersion 27', () async {
+      final db = AppDatabase(NativeDatabase.memory());
+      await db.select(db.accounts).get();
+
+      final allTables = await db
+          .customSelect("SELECT name FROM sqlite_master WHERE type='table'")
+          .get();
+      final tableNames = allTables.map((r) => r.read<String>('name')).toSet();
+      expect(
+        tableNames,
+        containsAll([
+          'accounts',
+          'mailboxes',
+          'emails',
+          'email_bodies',
+          'drafts',
+          'sync_states',
+          'pending_changes',
+          'sync_logs',
+          'sync_log_mailboxes',
+          'threads',
+          'sync_health',
+          'undo_actions',
+          'search_history_entries',
+        ]),
+      );
+
+      final emailColumns = await _tableColumns(db, 'emails');
+      expect(emailColumns, contains('list_unsubscribe_header'));
+
+      final draftColumns = await _tableColumns(db, 'drafts');
+      expect(draftColumns, contains('imap_server_id'));
+
       await db.close();
     });
   });

test/unit/reliability_runner_test.dart

@@ -0,0 +1,357 @@
+import 'dart:async';
+import 'package:fake_async/fake_async.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:sharedinbox/core/models/account.dart';
+import 'package:sharedinbox/core/models/email.dart';
+import 'package:sharedinbox/core/models/mailbox.dart';
+import 'package:sharedinbox/core/repositories/account_repository.dart';
+import 'package:sharedinbox/core/repositories/email_repository.dart';
+import 'package:sharedinbox/core/repositories/mailbox_repository.dart';
+import 'package:sharedinbox/core/repositories/sync_log_repository.dart';
+import 'package:sharedinbox/core/sync/account_sync_manager.dart';
+
+// ── helpers ───────────────────────────────────────────────────────────────────
+
+Account _account({String id = 'a1'}) => Account(
+      id: id,
+      displayName: 'Test',
+      email: 'test@example.com',
+      imapHost: 'localhost',
+    );
+
+class _FakeAccounts implements AccountRepository {
+  final List<Account> accounts;
+  _FakeAccounts([Account? account]) : accounts = [account ?? _account()];
+
+  @override
+  Stream<List<Account>> observeAccounts() => Stream.value(accounts);
+  @override
+  Future<Account?> getAccount(String id) async =>
+      accounts.cast<Account?>().firstWhere(
+            (a) => a?.id == id,
+            orElse: () => null,
+          );
+  @override
+  Future<void> addAccount(Account account, String password) async {}
+  @override
+  Future<void> updateAccount(Account account, {String? password}) async {}
+  @override
+  Future<void> removeAccount(String id) async {}
+  @override
+  Future<String> getPassword(String id) async => 'secret';
+}
+
+class _FakeMailboxes implements MailboxRepository {
+  final List<Mailbox> mailboxes;
+  _FakeMailboxes([this.mailboxes = const []]);
+  @override
+  Stream<List<Mailbox>> observeMailboxes(String? accountId) =>
+      Stream.value(mailboxes);
+  @override
+  Future<int> syncMailboxes(String accountId) async => 0;
+  @override
+  Future<Mailbox?> findMailboxByRole(String accountId, String role) async =>
+      null;
+  @override
+  Future<void> clearForResync(String accountId) async {}
+}
+
+class _CountingEmails implements EmailRepository {
+  int syncCount = 0;
+  int wakeUpCount = 0;
+  final Exception? syncError;
+
+  _CountingEmails({this.syncError});
+
+  @override
+  Future<SyncEmailsResult> syncEmails(String accountId, String mailbox) async {
+    syncCount++;
+    if (syncError != null) throw syncError!;
+    return SyncEmailsResult.zero;
+  }
+
+  @override
+  Future<int> wakeUpEmails(String accountId) async {
+    wakeUpCount++;
+    return 0;
+  }
+
+  @override
+  Future<int> flushPendingChanges(String accountId, String password) async => 0;
+  @override
+  Stream<List<Email>> observeEmails(
+    String a,
+    String m, {
+    int limit = 50,
+  }) =>
+      Stream.value([]);
+  @override
+  Stream<List<EmailThread>> observeThreads(
+    String a,
+    String m, {
+    int limit = 50,
+  }) =>
+      Stream.value([]);
+  @override
+  Stream<List<Email>> observeEmailsInThread(String a, String m, String t) =>
+      Stream.value([]);
+  @override
+  Future<Email?> getEmail(String id) async => null;
+  @override
+  Future<EmailBody> getEmailBody(String id) async =>
+      const EmailBody(emailId: '', attachments: []);
+  @override
+  Future<void> setFlag(String id, {bool? seen, bool? flagged}) async {}
+  @override
+  Future<void> moveEmail(String id, String dest) async {}
+  @override
+  Future<String?> deleteEmail(String id) async => null;
+  @override
+  Future<void> sendEmail(String accountId, EmailDraft draft) async {}
+  @override
+  Future<String> downloadAttachment(String id, EmailAttachment att) async => '';
+  @override
+  Future<List<Email>> searchEmails(String a, String m, String q) async => [];
+  @override
+  Future<List<Email>> searchEmailsGlobal(String? a, String q) async => [];
+  @override
+  Future<List<Email>> getEmailsByAddress(String? a, String addr) async => [];
+  @override
+  Stream<List<FailedMutation>> observeFailedMutations(String a) =>
+      Stream.value([]);
+  @override
+  Future<void> discardMutation(int id) async {}
+  @override
+  Future<void> retryMutation(int id) async {}
+  @override
+  Future<bool> cancelPendingChange(String id, String type) async => false;
+  @override
+  Future<void> snoozeEmail(String id, DateTime until) async {}
+  @override
+  Future<void> restoreEmails(List<Email> emails) async {}
+  @override
+  Stream<String> get onChangesQueued => const Stream.empty();
+  @override
+  Stream<void> watchJmapPush(String accountId, String password) =>
+      const Stream.empty();
+  @override
+  Future<ReliabilityResult> verifySyncReliability(
+    String accountId,
+    String mailboxPath,
+  ) async =>
+      ReliabilityResult.healthy;
+  @override
+  Future<void> clearForResync(String accountId) async {}
+}
+
+class _FakeSyncLog implements SyncLogRepository {
+  final logs = <bool>[];
+  @override
+  Future<void> log({
+    required String accountId,
+    required bool success,
+    String? errorMessage,
+    required String protocol,
+    required int emailsFetched,
+    required int emailsSkipped,
+    required int mailboxesSynced,
+    required int pendingFlushed,
+    required int bytesTransferred,
+    required DateTime startedAt,
+    required DateTime finishedAt,
+    List<MailboxSyncStats> mailboxStats = const [],
+    String? protocolLog,
+  }) async {
+    logs.add(success);
+  }
+
+  @override
+  Stream<List<SyncLogEntry>> observeSyncLogs(String accountId) =>
+      Stream.value([]);
+
+  @override
+  Stream<String?> observeLastError(String accountId) => Stream.value(null);
+}
+
+// ── tests ─────────────────────────────────────────────────────────────────────
+
+void main() {
+  group('AccountSyncManager backoff', () {
+    test('backoff is capped at 900 s after repeated failures', () {
+      fakeAsync((async) {
+        final emails = _CountingEmails(
+          syncError: Exception('connection refused'),
+        );
+        final syncLog = _FakeSyncLog();
+        final manager = AccountSyncManager(
+          _FakeAccounts(),
+          _FakeMailboxes([
+            const Mailbox(
+              id: 'INBOX',
+              accountId: 'a1',
+              path: 'INBOX',
+              name: 'Inbox',
+              unreadCount: 0,
+              totalCount: 0,
+            ),
+          ]),
+          emails,
+          syncLog: syncLog,
+          imapConnect: (_, __, ___) async =>
+              throw Exception('connection refused'),
+        );
+
+        manager.start();
+
+        // Advance 3 hours — long enough to observe many retries.
+        // With max backoff 900 s, we expect at least floor(3*3600/900) = 12
+        // attempts, and at most 3*3600/5 = 2160 (if backoff never grew).
+        async.elapse(const Duration(hours: 3));
+
+        final failCount = syncLog.logs.where((ok) => !ok).length;
+        expect(
+          failCount,
+          greaterThan(10),
+          reason: 'should have retried many times within 3 h',
+        );
+        expect(
+          failCount,
+          lessThan(2200),
+          reason: 'backoff must have kicked in — not every 5 s for 3 h',
+        );
+
+        manager.dispose();
+        async.elapse(const Duration(seconds: 1));
+      });
+    });
+
+    test('backoff resets to 5 s after a successful sync', () {
+      fakeAsync((async) {
+        int callCount = 0;
+        final syncLog = _FakeSyncLog();
+
+        var failsLeft = 5;
+        final customEmails = _OverrideEmails(
+          onSync: (_) async {
+            callCount++;
+            if (failsLeft > 0) {
+              failsLeft--;
+              throw Exception('transient error');
+            }
+            return SyncEmailsResult.zero;
+          },
+        );
+
+        final manager = AccountSyncManager(
+          _FakeAccounts(),
+          _FakeMailboxes([
+            const Mailbox(
+              id: 'INBOX',
+              accountId: 'a1',
+              path: 'INBOX',
+              name: 'Inbox',
+              unreadCount: 0,
+              totalCount: 0,
+            ),
+          ]),
+          customEmails,
+          syncLog: syncLog,
+          imapConnect: (_, __, ___) async =>
+              throw Exception('skip idle — force immediate loop'),
+        );
+
+        manager.start();
+
+        // Allow errors + backoff to build up, then a success, then more loops.
+        async.elapse(const Duration(seconds: 3600));
+
+        // After success, backoff should reset; failures before success should
+        // be exactly 5, and subsequent loops should fire frequently.
+        final successCount = syncLog.logs.where((ok) => ok).length;
+        expect(
+          successCount,
+          greaterThan(0),
+          reason: 'should have at least one success',
+        );
+        expect(
+          callCount,
+          greaterThan(5),
+          reason: 'should retry after failures and continue after success',
+        );
+
+        manager.dispose();
+        async.elapse(const Duration(seconds: 1));
+      });
+    });
+
+    test('concurrent sync errors from multiple accounts stay bounded', () {
+      fakeAsync((async) {
+        final accounts = _FakeAccounts()
+          ..accounts.add(_account(id: 'a2'))
+          ..accounts.add(_account(id: 'a3'));
+        final syncLog = _FakeSyncLog();
+        final manager = AccountSyncManager(
+          accounts,
+          _FakeMailboxes([
+            const Mailbox(
+              id: 'INBOX',
+              accountId: 'a1',
+              path: 'INBOX',
+              name: 'Inbox',
+              unreadCount: 0,
+              totalCount: 0,
+            ),
+            const Mailbox(
+              id: 'INBOX',
+              accountId: 'a2',
+              path: 'INBOX',
+              name: 'Inbox',
+              unreadCount: 0,
+              totalCount: 0,
+            ),
+            const Mailbox(
+              id: 'INBOX',
+              accountId: 'a3',
+              path: 'INBOX',
+              name: 'Inbox',
+              unreadCount: 0,
+              totalCount: 0,
+            ),
+          ]),
+          _CountingEmails(syncError: Exception('network error')),
+          syncLog: syncLog,
+          imapConnect: (_, __, ___) async =>
+              throw Exception('connection refused'),
+        );
+
+        manager.start();
+        async.elapse(const Duration(hours: 2));
+
+        // All 3 accounts retry, each bounded by the 900 s cap.
+        final failCount = syncLog.logs.where((ok) => !ok).length;
+        expect(failCount, greaterThan(5));
+        expect(
+          failCount,
+          lessThan(5000),
+          reason: 'backoff must be in effect across all accounts',
+        );
+
+        manager.dispose();
+        async.elapse(const Duration(seconds: 1));
+      });
+    });
+  });
+}
+
+// ── _OverrideEmails ───────────────────────────────────────────────────────────
+
+class _OverrideEmails extends _CountingEmails {
+  _OverrideEmails({required Future<SyncEmailsResult> Function(String) onSync})
+      : _onSync = onSync;
+
+  final Future<SyncEmailsResult> Function(String) _onSync;
+
+  @override
+  Future<SyncEmailsResult> syncEmails(String accountId, String mailbox) =>
+      _onSync(mailbox);
+}

test/unit/undo_service_test.mocks.dart

@@ -76,8 +76,9 @@ class MockEmailRepository extends _i1.Mock implements _i3.EmailRepository {
   @override
   _i4.Stream<List<_i2.Email>> observeEmails(
     String? accountId,
-    String? mailboxPath,
-  ) =>
+    String? mailboxPath, {
+    int? limit = 50,
+  }) =>
       (super.noSuchMethod(
         Invocation.method(
           #observeEmails,
@@ -85,6 +86,7 @@ class MockEmailRepository extends _i1.Mock implements _i3.EmailRepository {
             accountId,
             mailboxPath,
           ],
+          {#limit: limit},
         ),
         returnValue: _i4.Stream<List<_i2.Email>>.empty(),
       ) as _i4.Stream<List<_i2.Email>>);
@@ -92,8 +94,9 @@ class MockEmailRepository extends _i1.Mock implements _i3.EmailRepository {
   @override
   _i4.Stream<List<_i2.EmailThread>> observeThreads(
     String? accountId,
-    String? mailboxPath,
-  ) =>
+    String? mailboxPath, {
+    int? limit = 50,
+  }) =>
       (super.noSuchMethod(
         Invocation.method(
           #observeThreads,
@@ -101,6 +104,7 @@ class MockEmailRepository extends _i1.Mock implements _i3.EmailRepository {
             accountId,
             mailboxPath,
           ],
+          {#limit: limit},
         ),
         returnValue: _i4.Stream<List<_i2.EmailThread>>.empty(),
       ) as _i4.Stream<List<_i2.EmailThread>>);
@@ -452,6 +456,16 @@ class MockEmailRepository extends _i1.Mock implements _i3.EmailRepository {
           ),
         )),
       ) as _i4.Future<_i2.ReliabilityResult>);
+
+  @override
+  _i4.Future<void> clearForResync(String? accountId) => (super.noSuchMethod(
+        Invocation.method(
+          #clearForResync,
+          [accountId],
+        ),
+        returnValue: _i4.Future<void>.value(),
+        returnValueForMissingStub: _i4.Future<void>.value(),
+      ) as _i4.Future<void>);
 }
 
 /// A class which mocks [UndoRepository].

test/widget/helpers.dart

@@ -17,6 +17,7 @@ import 'package:sharedinbox/core/repositories/account_repository.dart';
 import 'package:sharedinbox/core/repositories/draft_repository.dart';
 import 'package:sharedinbox/core/repositories/email_repository.dart';
 import 'package:sharedinbox/core/repositories/mailbox_repository.dart';
+import 'package:sharedinbox/core/repositories/search_history_repository.dart';
 import 'package:sharedinbox/core/services/account_discovery_service.dart';
 import 'package:sharedinbox/core/services/connection_test_service.dart';
 import 'package:sharedinbox/core/services/managesieve_probe_service.dart';
@@ -30,6 +31,7 @@ import 'package:sharedinbox/ui/screens/email_detail_screen.dart';
 import 'package:sharedinbox/ui/screens/email_list_screen.dart';
 import 'package:sharedinbox/ui/screens/mailbox_list_screen.dart';
 import 'package:sharedinbox/ui/screens/search_screen.dart';
+import 'package:sharedinbox/ui/screens/thread_detail_screen.dart';
 
 // ---------------------------------------------------------------------------
 // Fake repositories
@@ -114,6 +116,9 @@ class FakeDraftRepository implements DraftRepository {
 
   @override
   Future<void> deleteDraft(int id) async => _drafts.remove(id);
+
+  @override
+  Future<void> syncDrafts(String accountId, String password) async {}
 }
 
 class FakeMailboxRepository implements MailboxRepository {
@@ -154,14 +159,19 @@ class FakeEmailRepository implements EmailRepository {
         _emailBody = emailBody ?? const EmailBody(emailId: '', attachments: []);
 
   @override
-  Stream<List<Email>> observeEmails(String accountId, String mailboxPath) =>
+  Stream<List<Email>> observeEmails(
+    String accountId,
+    String mailboxPath, {
+    int limit = 50,
+  }) =>
       Stream.value(List.of(_emails));
 
   @override
   Stream<List<EmailThread>> observeThreads(
     String accountId,
-    String mailboxPath,
-  ) =>
+    String mailboxPath, {
+    int limit = 50,
+  }) =>
       observeEmails(accountId, mailboxPath).map((emails) {
         return emails.map((e) {
           return EmailThread(
@@ -378,6 +388,18 @@ Widget buildApp({
                   ),
                 ],
               ),
+              GoRoute(
+                path: ':mailboxPath/threads/:threadId',
+                builder: (ctx, state) => ThreadDetailScreen(
+                  accountId: state.pathParameters['accountId']!,
+                  mailboxPath: Uri.decodeComponent(
+                    state.pathParameters['mailboxPath']!,
+                  ),
+                  threadId: Uri.decodeComponent(
+                    state.pathParameters['threadId']!,
+                  ),
+                ),
+              ),
             ],
           ),
         ],
@@ -487,3 +509,20 @@ Email testEmail({
       isFlagged: isFlagged,
       hasAttachment: hasAttachment,
     );
+
+class FakeSearchHistoryRepository implements SearchHistoryRepository {
+  final List<String> _history = [];
+
+  @override
+  Future<List<String>> getRecentSearches() async => List.unmodifiable(_history);
+
+  @override
+  Future<void> saveSearch(String query) async {
+    _history.remove(query);
+    _history.insert(0, query);
+    if (_history.length > 10) _history.removeLast();
+  }
+
+  @override
+  Future<void> clearHistory() async => _history.clear();
+}

test/widget/search_screen_test.dart

@@ -0,0 +1,201 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:sharedinbox/core/models/mailbox.dart';
+import 'package:sharedinbox/di.dart';
+
+import 'helpers.dart';
+
+void main() {
+  group('SearchScreen', () {
+    testWidgets('shows placeholder hint text when empty', (tester) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+            searchHistoryRepositoryProvider.overrideWithValue(
+              FakeSearchHistoryRepository(),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.text('Type 3+ characters to search'), findsOneWidget);
+    });
+
+    testWidgets('typing fewer than 3 characters does not trigger search', (
+      tester,
+    ) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+            searchHistoryRepositoryProvider.overrideWithValue(
+              FakeSearchHistoryRepository(),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'hi');
+      await tester.pump(const Duration(milliseconds: 400));
+
+      expect(find.text('Type 3+ characters to search'), findsOneWidget);
+      expect(find.text('No results'), findsNothing);
+    });
+
+    testWidgets('shows "No results" when search returns nothing', (
+      tester,
+    ) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+            searchHistoryRepositoryProvider.overrideWithValue(
+              FakeSearchHistoryRepository(),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'xyz');
+      await tester.pump(const Duration(milliseconds: 400));
+      await tester.pumpAndSettle();
+
+      expect(find.text('No results'), findsOneWidget);
+    });
+
+    testWidgets('shows email results under "Messages" section', (
+      tester,
+    ) async {
+      final email = testEmail(subject: 'Invoice Q3');
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(searchResults: [email]),
+            ),
+            searchHistoryRepositoryProvider.overrideWithValue(
+              FakeSearchHistoryRepository(),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'inv');
+      await tester.pump(const Duration(milliseconds: 400));
+      await tester.pumpAndSettle();
+
+      expect(find.text('Messages'), findsOneWidget);
+      expect(find.text('Invoice Q3'), findsOneWidget);
+    });
+
+    testWidgets('shows folder results under "Folders" section', (
+      tester,
+    ) async {
+      const archiveMailbox = Mailbox(
+        id: 'acc-1:Archive',
+        accountId: 'acc-1',
+        path: 'Archive',
+        name: 'Archive',
+        unreadCount: 0,
+        totalCount: 5,
+      );
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository([archiveMailbox]),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+            searchHistoryRepositoryProvider.overrideWithValue(
+              FakeSearchHistoryRepository(),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'arc');
+      await tester.pump(const Duration(milliseconds: 400));
+      await tester.pumpAndSettle();
+
+      expect(find.text('Folders'), findsOneWidget);
+      expect(find.text('Archive'), findsOneWidget);
+    });
+
+    testWidgets('tapping clear button resets results to placeholder', (
+      tester,
+    ) async {
+      final email = testEmail(subject: 'Found email');
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/search',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(searchResults: [email]),
+            ),
+            searchHistoryRepositoryProvider.overrideWithValue(
+              FakeSearchHistoryRepository(),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      await tester.enterText(find.byType(TextField), 'found');
+      await tester.pump(const Duration(milliseconds: 400));
+      await tester.pumpAndSettle();
+      expect(find.text('Found email'), findsOneWidget);
+
+      await tester.tap(find.byIcon(Icons.clear));
+      await tester.pumpAndSettle();
+
+      // Results are gone; the recent-search chip for the prior query appears.
+      expect(find.text('Found email'), findsNothing);
+      expect(find.text('found'), findsOneWidget);
+    });
+  });
+}

test/widget/thread_detail_screen_test.dart

@@ -0,0 +1,198 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'package:sharedinbox/core/models/email.dart';
+import 'package:sharedinbox/di.dart';
+
+import 'helpers.dart';
+
+Email _threadEmail({
+  String id = 'acc-1:10',
+  bool isFlagged = false,
+  bool isSeen = true,
+}) =>
+    Email(
+      id: id,
+      accountId: 'acc-1',
+      mailboxPath: 'INBOX',
+      uid: 10,
+      threadId: 'thread-1',
+      subject: 'Project update',
+      receivedAt: DateTime(2024, 6),
+      sentAt: DateTime(2024, 6, 1, 9),
+      from: const [EmailAddress(name: 'Bob', email: 'bob@example.com')],
+      to: const [EmailAddress(email: 'alice@example.com')],
+      cc: const [],
+      isSeen: isSeen,
+      isFlagged: isFlagged,
+      hasAttachment: false,
+    );
+
+void main() {
+  group('ThreadDetailScreen', () {
+    testWidgets('shows "Thread not found or empty" when thread is empty', (
+      tester,
+    ) async {
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(FakeEmailRepository()),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.text('Thread not found or empty'), findsOneWidget);
+    });
+
+    testWidgets('shows sender name for email in thread', (tester) async {
+      final email = _threadEmail();
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(emails: [email]),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.textContaining('Bob'), findsOneWidget);
+    });
+
+    testWidgets('last email in thread is expanded by default', (tester) async {
+      final email = _threadEmail();
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(
+                emails: [email],
+                emailBody: const EmailBody(
+                  emailId: 'acc-1:10',
+                  textBody: 'Hello body text',
+                  attachments: [],
+                ),
+              ),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      // Reply and delete buttons are visible for the expanded card.
+      expect(find.byIcon(Icons.reply), findsOneWidget);
+      expect(find.byIcon(Icons.delete_outline), findsOneWidget);
+    });
+
+    testWidgets('tapping an expanded card collapses it', (tester) async {
+      final email = _threadEmail();
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(
+                emails: [email],
+                emailBody: const EmailBody(
+                  emailId: 'acc-1:10',
+                  textBody: 'Hello body text',
+                  attachments: [],
+                ),
+              ),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      // Tap the expand_less icon to collapse.
+      await tester.tap(find.byIcon(Icons.expand_less));
+      await tester.pumpAndSettle();
+
+      expect(find.byIcon(Icons.reply), findsNothing);
+      expect(find.byIcon(Icons.expand_more), findsOneWidget);
+    });
+
+    testWidgets('flagged email shows star icon', (tester) async {
+      final email = _threadEmail(isFlagged: true);
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(emails: [email]),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.byIcon(Icons.star), findsOneWidget);
+    });
+
+    testWidgets('expanded card shows plain text body', (tester) async {
+      final email = _threadEmail();
+      await tester.pumpWidget(
+        buildApp(
+          initialLocation: '/accounts/acc-1/mailboxes/INBOX/threads/thread-1',
+          overrides: [
+            accountRepositoryProvider.overrideWithValue(
+              FakeAccountRepository([kTestAccount]),
+            ),
+            mailboxRepositoryProvider.overrideWithValue(
+              FakeMailboxRepository(),
+            ),
+            emailRepositoryProvider.overrideWithValue(
+              FakeEmailRepository(
+                emails: [email],
+                emailBody: const EmailBody(
+                  emailId: 'acc-1:10',
+                  textBody: 'Body content here',
+                  attachments: [],
+                ),
+              ),
+            ),
+          ],
+        ),
+      );
+      await tester.pumpAndSettle();
+
+      expect(find.text('Body content here'), findsOneWidget);
+    });
+  });
+}