refactor(A1): extract EmailDetailNotifier, drop initState DB coupling

EmailDetailScreen no longer calls the repository directly in initState.
A new EmailDetailNotifier (AsyncNotifierProvider.autoDispose.family) owns
the load + setFlag(seen) side effect; the screen watches the provider and
renders via detail.when(loading/error/data).

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

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}"

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

@@ -99,4 +99,9 @@ abstract class EmailRepository {
     String accountId,
     String mailboxPath,
   );
+
+  /// Deletes all locally-cached email rows and pending changes for [accountId],
+  /// while preserving EmailBodies so already-downloaded content is not lost.
+  /// Also resets sync-state checkpoints so the next sync fetches everything fresh.
+  Future<void> clearForResync(String accountId);
 }

lib/core/repositories/mailbox_repository.dart

@@ -8,4 +8,7 @@ abstract class MailboxRepository {
 
   /// Returns the first mailbox with the given [role] for [accountId], or null.
   Future<Mailbox?> findMailboxByRole(String accountId, String role);
+
+  /// Deletes all locally-cached mailbox rows for [accountId].
+  Future<void> clearForResync(String accountId);
 }

lib/core/repositories/sync_log_repository.dart

@@ -65,6 +65,10 @@ abstract class SyncLogRepository {
   });
 
   Stream<List<SyncLogEntry>> observeSyncLogs(String accountId);
+
+  /// Emits the error message of the most recent sync attempt for [accountId],
+  /// or null when the last sync succeeded (or no syncs have run yet).
+  Stream<String?> observeLastError(String accountId);
 }
 
 class NoOpSyncLogRepository implements SyncLogRepository {
@@ -90,4 +94,7 @@ class NoOpSyncLogRepository implements SyncLogRepository {
   @override
   Stream<List<SyncLogEntry>> observeSyncLogs(String accountId) =>
       Stream.value([]);
+
+  @override
+  Stream<String?> observeLastError(String accountId) => Stream.value(null);
 }

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/services/undo_service.dart

@@ -10,12 +10,19 @@ class UndoService extends StateNotifier<List<UndoAction>> {
   final Ref _ref;
   static const int _maxHistory = 10;
 
+  // Resolves once init() has loaded persisted history. Default to an already-
+  // resolved future so operations are safe even if init() is never called.
+  Future<void> _ready = Future.value();
+
   Future<void> init() async {
-    final repo = _ref.read(undoRepositoryProvider);
-    state = await repo.getHistory();
+    _ready = _ref.read(undoRepositoryProvider).getHistory().then((history) {
+      if (mounted) state = history;
+    });
+    await _ready;
   }
 
-  void pushAction(UndoAction action) {
+  Future<void> pushAction(UndoAction action) async {
+    await _ready;
     final newList = [...state, action];
     if (newList.length > _maxHistory) {
       final removed = newList.removeAt(0);
@@ -25,12 +32,14 @@ class UndoService extends StateNotifier<List<UndoAction>> {
     unawaited(_ref.read(undoRepositoryProvider).saveAction(action));
   }
 
-  void clear() {
+  Future<void> clear() async {
+    await _ready;
     state = [];
     unawaited(_ref.read(undoRepositoryProvider).clearHistory());
   }
 
   Future<void> undo({String? actionId}) async {
+    await _ready;
     if (state.isEmpty) return;
 
     final UndoAction action;

lib/core/sync/account_sync_manager.dart

@@ -4,6 +4,7 @@ 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';
@@ -11,6 +12,8 @@ import 'package:sharedinbox/core/utils/logger.dart';
 import 'package:sharedinbox/data/imap/imap_client_factory.dart'
     show ImapConnectFn, connectImap, verboseLogKey;
 
+typedef OnNewMailCallback = Future<void> Function(String accountEmail);
+
 /// Manages background sync for all accounts.
 ///
 /// IMAP accounts get an IDLE-based sync loop (_AccountSync).
@@ -22,19 +25,35 @@ 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 +64,7 @@ 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 +73,10 @@ class AccountSyncManager {
               _emails,
               _imapConnect,
               _syncLog,
+              _drafts,
+              _onNewMail,
+              onSyncStart: () => _emitSyncing(id, syncing: true),
+              onSyncEnd: () => _emitSyncing(id, syncing: false),
             ),
           AccountType.jmap => _JmapAccountSync(
               account,
@@ -60,6 +84,8 @@ class AccountSyncManager {
               _emails,
               _accounts,
               _syncLog,
+              onSyncStart: () => _emitSyncing(id, syncing: true),
+              onSyncEnd: () => _emitSyncing(id, syncing: false),
             ),
         };
         _active[account.id] = loop;
@@ -81,6 +107,7 @@ class AccountSyncManager {
       s.stop();
     }
     _active.clear();
+    unawaited(_syncPhaseCtrl.close());
   }
 
   /// Wakes the idle/wait phase of the given account's sync loop so a new
@@ -88,6 +115,49 @@ class AccountSyncManager {
   void syncNow(String accountId) {
     _active[accountId]?.kick();
   }
+
+  /// Clears all locally-cached emails and mailboxes for [accountId], then
+  /// immediately starts a fresh sync cycle. Use this as an escape hatch when
+  /// the local DB is believed to be out of sync with the server.
+  Future<void> forceResync(String accountId) async {
+    _active.remove(accountId)?.stop();
+
+    await _emails.clearForResync(accountId);
+    await _mailboxes.clearForResync(accountId);
+
+    final accounts = await _accounts.observeAccounts().first;
+    final account = accounts.cast<Account?>().firstWhere(
+          (a) => a?.id == accountId,
+          orElse: () => null,
+        );
+    if (account == null) return;
+
+    final loop = switch (account.type) {
+      AccountType.imap => _AccountSync(
+          account,
+          _accounts,
+          _mailboxes,
+          _emails,
+          _imapConnect,
+          _syncLog,
+          _drafts,
+          _onNewMail,
+          onSyncStart: () => _emitSyncing(accountId, syncing: true),
+          onSyncEnd: () => _emitSyncing(accountId, syncing: false),
+        ),
+      AccountType.jmap => _JmapAccountSync(
+          account,
+          _mailboxes,
+          _emails,
+          _accounts,
+          _syncLog,
+          onSyncStart: () => _emitSyncing(accountId, syncing: true),
+          onSyncEnd: () => _emitSyncing(accountId, syncing: false),
+        ),
+    };
+    _active[accountId] = loop;
+    loop.start();
+  }
 }
 
 // ── Shared interface ──────────────────────────────────────────────────────────
@@ -108,7 +178,12 @@ 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;
@@ -116,6 +191,10 @@ 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;
@@ -148,6 +227,7 @@ 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,
@@ -167,8 +247,10 @@ 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(
@@ -242,6 +324,8 @@ 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);
 
@@ -288,6 +372,7 @@ class _AccountSync implements _SyncLoop {
       await client.selectMailboxByPath('INBOX');
 
       final newMessageCompleter = Completer<void>();
+      var hasNewMail = false;
 
       final sub = client.eventBus
           .on<imap.ImapEvent>()
@@ -295,7 +380,11 @@ 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();
       });
 
@@ -311,6 +400,10 @@ class _AccountSync implements _SyncLoop {
 
       await client.idleDone();
       await sub.cancel();
+
+      if (hasNewMail) {
+        unawaited(_onNewMail?.call(account.email));
+      }
     } finally {
       await client.logout();
       _idleClient = null;
@@ -327,14 +420,19 @@ 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;
@@ -366,6 +464,7 @@ 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,
@@ -385,8 +484,10 @@ 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(

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 +230,8 @@ 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('UndoActionRow')
@@ -264,7 +269,7 @@ class AppDatabase extends _$AppDatabase {
   AppDatabase([QueryExecutor? executor]) : super(executor ?? _openConnection());
 
   @override
-  int get schemaVersion => 22;
+  int get schemaVersion => 25;
 
   @override
   MigrationStrategy get migration => MigrationStrategy(
@@ -420,6 +425,28 @@ 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);',
+              ),
+            );
+          }
         },
       );
 }

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

@@ -528,7 +528,7 @@ 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 +569,7 @@ 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 +613,7 @@ class EmailRepositoryImpl implements EmailRepository {
                 inReplyTo: Value(inReplyTo),
                 references: Value(refs),
                 snoozedUntil: Value(snoozedUntil),
+                listUnsubscribeHeader: Value(listUnsubscribe),
               ),
             );
       }
@@ -950,6 +952,7 @@ class EmailRepositoryImpl implements EmailRepository {
     'htmlBody',
     'bodyValues',
     'attachments',
+    'header:List-Unsubscribe:asText',
   ];
 
   static const _emailGetBodyOptions = {
@@ -1151,6 +1154,8 @@ 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 +1178,7 @@ class EmailRepositoryImpl implements EmailRepository {
               inReplyTo: Value(jmapInReplyTo),
               references: Value(jmapReferences),
               snoozedUntil: Value(snoozedUntil),
+              listUnsubscribeHeader: Value(jmapListUnsubscribe),
             ),
           );
 
@@ -2663,6 +2669,7 @@ class EmailRepositoryImpl implements EmailRepository {
       references: row.references,
       snoozedUntil: row.snoozedUntil,
       snoozedFromMailboxPath: row.snoozedFromMailboxPath,
+      listUnsubscribeHeader: row.listUnsubscribeHeader,
     );
   }
 
@@ -2739,4 +2746,27 @@ class EmailRepositoryImpl implements EmailRepository {
       const PendingChangesCompanion(attempts: Value(0), lastError: Value(null)),
     );
   }
+
+  @override
+  Future<void> clearForResync(String accountId) async {
+    // Disable FK constraints so EmailBodies rows survive the emails deletion.
+    // When emails are re-inserted after the next sync with the same IDs, the
+    // cached body content will be reused without a network round-trip.
+    await _db.customStatement('PRAGMA foreign_keys = OFF');
+    try {
+      await _db.transaction(() async {
+        await (_db.delete(_db.emails)
+              ..where((t) => t.accountId.equals(accountId)))
+            .go();
+        await (_db.delete(_db.pendingChanges)
+              ..where((t) => t.accountId.equals(accountId)))
+            .go();
+        await (_db.delete(_db.syncStates)
+              ..where((t) => t.accountId.equals(accountId)))
+            .go();
+      });
+    } finally {
+      await _db.customStatement('PRAGMA foreign_keys = ON');
+    }
+  }
 }

lib/data/repositories/mailbox_repository_impl.dart

@@ -303,4 +303,11 @@ class MailboxRepositoryImpl implements MailboxRepository {
     if (mb.isJunk) return 'junk';
     return null;
   }
+
+  @override
+  Future<void> clearForResync(String accountId) async {
+    await (_db.delete(_db.mailboxes)
+          ..where((t) => t.accountId.equals(accountId)))
+        .go();
+  }
 }

lib/data/repositories/sync_log_repository_impl.dart

@@ -99,4 +99,14 @@ class SyncLogRepositoryImpl implements SyncLogRepository {
       return entries;
     });
   }
+
+  @override
+  Stream<String?> observeLastError(String accountId) {
+    return (_db.select(_db.syncLogs)
+          ..where((t) => t.accountId.equals(accountId))
+          ..orderBy([(t) => OrderingTerm.desc(t.startedAt)])
+          ..limit(1))
+        .watchSingleOrNull()
+        .map((row) => (row?.result == 'error') ? row?.errorMessage : null);
+  }
 }

lib/di.dart

@@ -3,6 +3,7 @@ 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';
@@ -12,11 +13,12 @@ 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';
@@ -65,7 +67,11 @@ 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) {
@@ -85,6 +91,11 @@ final syncLogRepositoryProvider = Provider((ref) {
   return SyncLogRepositoryImpl(ref.watch(dbProvider));
 });
 
+final syncLastErrorProvider =
+    StreamProvider.autoDispose.family<String?, String>((ref, accountId) {
+  return ref.watch(syncLogRepositoryProvider).observeLastError(accountId);
+});
+
 final reliabilityRunnerProvider = Provider<ReliabilityRunner>((ref) {
   final runner = ReliabilityRunner(
     ref.watch(dbProvider),
@@ -105,6 +116,11 @@ 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),
@@ -112,6 +128,8 @@ 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;
@@ -151,6 +169,27 @@ 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

@@ -43,6 +43,7 @@ class _EditAccountScreenState extends ConsumerState<EditAccountScreen> {
   bool _tryTesting = false;
   String? _tryOk;
   String? _tryErr;
+  bool _resyncing = false;
 
   @override
   void initState() {
@@ -170,6 +171,43 @@ class _EditAccountScreenState extends ConsumerState<EditAccountScreen> {
     }
   }
 
+  Future<void> _forceResync() async {
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('Force full sync?'),
+        content: const Text(
+          'This clears all locally-cached emails and mailboxes for this '
+          'account and immediately re-downloads everything from the server. '
+          'Previously viewed email content will not need to be re-downloaded.',
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.of(ctx).pop(false),
+            child: const Text('Cancel'),
+          ),
+          FilledButton(
+            onPressed: () => Navigator.of(ctx).pop(true),
+            child: const Text('Force sync'),
+          ),
+        ],
+      ),
+    );
+    if (confirmed != true || !mounted) return;
+    setState(() => _resyncing = true);
+    try {
+      await ref.read(syncManagerProvider).forceResync(widget.accountId);
+      if (mounted) context.pop();
+    } catch (e) {
+      if (mounted) {
+        setState(() {
+          _resyncing = false;
+          _errorMessage = 'Force sync failed: $e';
+        });
+      }
+    }
+  }
+
   Future<void> _save() async {
     if (!_formKey.currentState!.validate()) return;
     final password = _passwordCtrl.text.isNotEmpty ? _passwordCtrl.text : null;
@@ -230,11 +268,9 @@ class _EditAccountScreenState extends ConsumerState<EditAccountScreen> {
   Widget build(BuildContext context) {
     return Scaffold(
       appBar: AppBar(title: const Text('Edit account')),
-      body: _loading
+      body: _loading || _saving || _resyncing
           ? const Center(child: CircularProgressIndicator())
-          : _saving
-              ? const Center(child: CircularProgressIndicator())
-              : _buildForm(),
+          : _buildForm(),
     );
   }
 
@@ -288,11 +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(
@@ -312,6 +348,7 @@ class _EditAccountScreenState extends ConsumerState<EditAccountScreen> {
                     _sieveHostCtrl,
                     'Host (leave blank to use IMAP host)',
                     required: false,
+                    validator: validateOptionalHostname,
                   ),
                   _field(
                     _sievePortCtrl,
@@ -350,6 +387,15 @@ class _EditAccountScreenState extends ConsumerState<EditAccountScreen> {
             ),
             const SizedBox(height: 8),
             FilledButton(onPressed: _save, child: const Text('Save')),
+            const SizedBox(height: 8),
+            OutlinedButton.icon(
+              icon: const Icon(Icons.sync_problem),
+              label: const Text('Force full sync'),
+              style: OutlinedButton.styleFrom(
+                foregroundColor: Theme.of(context).colorScheme.error,
+              ),
+              onPressed: _forceResync,
+            ),
           ],
         ),
       ),
@@ -363,6 +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),
@@ -375,9 +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');
 
@@ -25,142 +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) {
-                    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),
+      ),
     );
   }
 
@@ -183,7 +172,7 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
                 ),
               ),
             ),
-          Html(
+          _SafeHtml(
             data: body.htmlBody!,
             extensions: [if (!_loadRemoteImages) _BlockRemoteImagesExtension()],
           ),
@@ -265,6 +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!),
+          ),
       ],
     );
   }
@@ -354,16 +348,18 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
 
     await ref.read(emailRepositoryProvider).moveEmail(widget.emailId, chosen);
 
-    ref.read(undoServiceProvider.notifier).pushAction(
-          UndoAction(
-            id: DateTime.now().toIso8601String(),
-            accountId: header.accountId,
-            type: UndoType.move,
-            emailIds: [widget.emailId],
-            sourceMailboxPath: header.mailboxPath,
-            destinationMailboxPath: chosen,
+    unawaited(
+      ref.read(undoServiceProvider.notifier).pushAction(
+            UndoAction(
+              id: DateTime.now().toIso8601String(),
+              accountId: header.accountId,
+              type: UndoType.move,
+              emailIds: [widget.emailId],
+              sourceMailboxPath: header.mailboxPath,
+              destinationMailboxPath: chosen,
+            ),
           ),
-        );
+    );
 
     if (context.mounted) context.pop();
   }
@@ -384,7 +380,7 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
       sourceMailboxPath: header.mailboxPath,
       originalEmails: [header],
     );
-    ref.read(undoServiceProvider.notifier).pushAction(action);
+    unawaited(ref.read(undoServiceProvider.notifier).pushAction(action));
     await repo.snoozeEmail(widget.emailId, until);
 
     if (context.mounted) {
@@ -458,6 +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';
 
@@ -35,6 +36,9 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
   bool _searchLoading = false;
   bool get _searching => _searchController.text.isNotEmpty;
 
+  // Error banner — tracks the last error message that the user dismissed.
+  String? _dismissedError;
+
   // Thread-level selection (key = threadId).
   final Set<String> _selectedThreadIds = {};
   // Last-emitted thread list, used to resolve emailIds for batch operations.
@@ -131,9 +135,16 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
               currentMailboxPath: widget.mailboxPath,
             ),
       bottomNavigationBar: _selecting ? _selectionBottomBar() : null,
-      body: (_searchResults != null || _searchLoading)
-          ? _buildSearchBody()
-          : _buildStreamBody(repo),
+      body: Column(
+        children: [
+          _buildSyncErrorBanner(),
+          Expanded(
+            child: (_searchResults != null || _searchLoading)
+                ? _buildSearchBody()
+                : _buildStreamBody(repo),
+          ),
+        ],
+      ),
     );
   }
 
@@ -170,22 +181,7 @@ 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(
@@ -219,6 +215,44 @@ 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(
@@ -267,6 +301,39 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
     return _buildEmailList(_searchResults!);
   }
 
+  Widget _buildSyncErrorBanner() {
+    final errorAsync = ref.watch(syncLastErrorProvider(widget.accountId));
+    final error = errorAsync.valueOrNull;
+    if (error == null || error == _dismissedError) {
+      return const SizedBox.shrink();
+    }
+    return MaterialBanner(
+      padding: const EdgeInsets.fromLTRB(16, 8, 8, 8),
+      content: Text(
+        error,
+        maxLines: 2,
+        overflow: TextOverflow.ellipsis,
+      ),
+      leading: Icon(
+        Icons.sync_problem,
+        color: Theme.of(context).colorScheme.error,
+      ),
+      backgroundColor: Theme.of(context).colorScheme.errorContainer,
+      actions: [
+        TextButton(
+          onPressed: () {
+            ref.read(syncManagerProvider).syncNow(widget.accountId);
+          },
+          child: const Text('Retry'),
+        ),
+        TextButton(
+          onPressed: () => setState(() => _dismissedError = error),
+          child: const Text('Dismiss'),
+        ),
+      ],
+    );
+  }
+
   Widget _buildStreamBody(EmailRepository emailRepo) {
     return RefreshIndicator(
       onRefresh: () async {
@@ -331,7 +398,7 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
       destinationMailboxPath: mailbox.path,
       originalEmails: originalEmails,
     );
-    ref.read(undoServiceProvider.notifier).pushAction(action);
+    unawaited(ref.read(undoServiceProvider.notifier).pushAction(action));
   }
 
   Future<void> _batchArchive() =>
@@ -364,7 +431,7 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
       destinationMailboxPath: lastDestPath,
       originalEmails: originalEmails,
     );
-    ref.read(undoServiceProvider.notifier).pushAction(action);
+    unawaited(ref.read(undoServiceProvider.notifier).pushAction(action));
   }
 
   Future<void> _batchMarkSpam() =>
@@ -426,7 +493,7 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
       destinationMailboxPath: chosen,
       originalEmails: originalEmails,
     );
-    ref.read(undoServiceProvider.notifier).pushAction(action);
+    unawaited(ref.read(undoServiceProvider.notifier).pushAction(action));
   }
 
   Future<void> _batchSnooze() async {
@@ -458,7 +525,7 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
       sourceMailboxPath: widget.mailboxPath,
       originalEmails: originalEmails,
     );
-    ref.read(undoServiceProvider.notifier).pushAction(action);
+    unawaited(ref.read(undoServiceProvider.notifier).pushAction(action));
 
     if (!mounted) return;
 
@@ -609,7 +676,9 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
                 destinationMailboxPath: archive.path,
                 originalEmails: originalEmails,
               );
-              ref.read(undoServiceProvider.notifier).pushAction(action);
+              unawaited(
+                ref.read(undoServiceProvider.notifier).pushAction(action),
+              );
             } else {
               String? lastDestPath;
               for (final id in t.emailIds) {
@@ -625,7 +694,9 @@ class _EmailListScreenState extends ConsumerState<EmailListScreen> {
                 destinationMailboxPath: lastDestPath,
                 originalEmails: originalEmails,
               );
-              ref.read(undoServiceProvider.notifier).pushAction(action);
+              unawaited(
+                ref.read(undoServiceProvider.notifier).pushAction(action),
+              );
             }
           },
           child: tile,
@@ -641,10 +712,9 @@ 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
@@ -652,25 +722,7 @@ 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 +8,7 @@ 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';
 
 class SearchScreen extends ConsumerStatefulWidget {
   const SearchScreen({super.key, this.accountId});
@@ -155,7 +156,15 @@ 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/${Uri.encodeComponent(e.id)}',
+              ),
+            ),
         ],
       ],
     );
@@ -246,42 +255,3 @@ class _AddressTile extends StatelessWidget {
     );
   }
 }
-
-class _EmailTile extends StatelessWidget {
-  const _EmailTile({required this.email, required this.accountId});
-  final Email email;
-  final String accountId;
-
-  @override
-  Widget build(BuildContext context) {
-    final sender = email.from.isNotEmpty
-        ? (email.from.first.name ?? email.from.first.email)
-        : '(unknown)';
-    return ListTile(
-      leading: Icon(
-        email.isSeen ? Icons.mail_outline : Icons.mail,
-        color: email.isSeen ? null : Theme.of(context).colorScheme.primary,
-      ),
-      title: Text(sender),
-      subtitle: Column(
-        crossAxisAlignment: CrossAxisAlignment.start,
-        children: [
-          Text(
-            email.subject ?? '(no subject)',
-            maxLines: 1,
-            overflow: TextOverflow.ellipsis,
-          ),
-          Text(
-            '$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/screens/thread_detail_screen.dart

@@ -256,17 +256,19 @@ class _EmailMessageCardState extends ConsumerState<_EmailMessageCard> {
       final destPath = await repo.deleteEmail(widget.email.id);
 
       if (original != null) {
-        ref.read(undoServiceProvider.notifier).pushAction(
-              UndoAction(
-                id: DateTime.now().toIso8601String(),
-                accountId: widget.email.accountId,
-                type: UndoType.delete,
-                emailIds: [widget.email.id],
-                sourceMailboxPath: widget.email.mailboxPath,
-                destinationMailboxPath: destPath,
-                originalEmails: [original],
+        unawaited(
+          ref.read(undoServiceProvider.notifier).pushAction(
+                UndoAction(
+                  id: DateTime.now().toIso8601String(),
+                  accountId: widget.email.accountId,
+                  type: UndoType.delete,
+                  emailIds: [widget.email.id],
+                  sourceMailboxPath: widget.email.mailboxPath,
+                  destinationMailboxPath: destPath,
+                  originalEmails: [original],
+                ),
               ),
-            );
+        );
       }
     }
   }

lib/ui/screens/undo_log_screen.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:intl/intl.dart';
@@ -22,7 +24,8 @@ class UndoLogScreen extends ConsumerWidget {
             tooltip: 'Clear history',
             onPressed: history.isEmpty
                 ? null
-                : () => ref.read(undoServiceProvider.notifier).clear(),
+                : () =>
+                    unawaited(ref.read(undoServiceProvider.notifier).clear()),
           ),
         ],
       ),

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,
+    );
+  }
+}

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

@@ -52,6 +52,7 @@ 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',

test/integration/account_sync_manager_test.dart

@@ -96,6 +96,9 @@ class _FakeMailboxes implements MailboxRepository {
   @override
   Future<Mailbox?> findMailboxByRole(String accountId, String role) async =>
       null;
+
+  @override
+  Future<void> clearForResync(String accountId) async {}
 }
 
 class _FakeEmails implements EmailRepository {
@@ -191,6 +194,9 @@ class _FakeEmails implements EmailRepository {
 
   @override
   Future<void> retryMutation(int id) async {}
+
+  @override
+  Future<void> clearForResync(String accountId) async {}
 }
 
 class _FakeLogs implements SyncLogRepository {
@@ -214,4 +220,7 @@ class _FakeLogs implements SyncLogRepository {
   @override
   Stream<List<SyncLogEntry>> observeSyncLogs(String accountId) =>
       Stream.value([]);
+
+  @override
+  Stream<String?> observeLastError(String accountId) => Stream.value(null);
 }

test/unit/account_sync_manager_test.dart

@@ -98,6 +98,9 @@ class FakeEmailRepository implements EmailRepository {
     String mailboxPath,
   ) async =>
       ReliabilityResult.healthy;
+
+  @override
+  Future<void> clearForResync(String accountId) async {}
 }
 
 class _Log {
@@ -129,6 +132,9 @@ class FakeSyncLogRepository implements SyncLogRepository {
   @override
   Stream<List<SyncLogEntry>> observeSyncLogs(String accountId) =>
       Stream.value([]);
+
+  @override
+  Stream<String?> observeLastError(String accountId) => Stream.value(null);
 }
 
 class FakeMailboxRepositoryWithInbox implements MailboxRepository {
@@ -148,4 +154,6 @@ class FakeMailboxRepositoryWithInbox implements MailboxRepository {
   Future<int> syncMailboxes(String id) async => 1;
   @override
   Future<Mailbox?> findMailboxByRole(String id, String role) async => null;
+  @override
+  Future<void> clearForResync(String accountId) async {}
 }

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].
@@ -582,4 +592,14 @@ 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_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/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, 25);
+      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 +78,240 @@ 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
+        ]),
+      );
+
       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'));
+
+      await db.close();
+      if (dbFile.existsSync()) dbFile.deleteSync();
+    });
+
+    test('fresh install creates all tables at schemaVersion 25', () 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',
+        ]),
+      );
+
+      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 +1,348 @@
+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) => Stream.value([]);
+  @override
+  Stream<List<EmailThread>> observeThreads(String a, String m) =>
+      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_logic_test.dart

@@ -109,7 +109,7 @@ void main() {
       sourceMailboxPath: 'INBOX',
       originalEmails: [original!],
     );
-    container.read(undoServiceProvider.notifier).pushAction(action);
+    await container.read(undoServiceProvider.notifier).pushAction(action);
     await container.read(undoServiceProvider.notifier).undo();
 
     // 3. Verify it is back in Inbox
@@ -190,7 +190,7 @@ void main() {
       emailIds: [emailId],
       sourceMailboxPath: 'INBOX',
     );
-    container.read(undoServiceProvider.notifier).pushAction(action);
+    await container.read(undoServiceProvider.notifier).pushAction(action);
     await container.read(undoServiceProvider.notifier).undo();
 
     // 3. Verify it is back in Inbox
@@ -230,7 +230,7 @@ void main() {
         destinationMailboxPath: destPath,
         originalEmails: [original!],
       );
-      container.read(undoServiceProvider.notifier).pushAction(action);
+      await container.read(undoServiceProvider.notifier).pushAction(action);
       await container.read(undoServiceProvider.notifier).undo();
 
       // 4. Verify local state
@@ -273,7 +273,7 @@ void main() {
       sourceMailboxPath: 'INBOX',
       originalEmails: [original!],
     );
-    container.read(undoServiceProvider.notifier).pushAction(action);
+    await container.read(undoServiceProvider.notifier).pushAction(action);
     await container.read(undoServiceProvider.notifier).undo();
 
     // 3. Verify it is back in Inbox and metadata is cleared

test/unit/undo_service_test.dart

@@ -61,10 +61,10 @@ void main() {
     final notifier = container.read(undoServiceProvider.notifier);
     await notifier.init(); // Wait for persistent load
 
-    notifier.pushAction(action1);
+    await notifier.pushAction(action1);
     expect(container.read(undoServiceProvider), [action1]);
 
-    notifier.pushAction(action2);
+    await notifier.pushAction(action2);
     expect(container.read(undoServiceProvider), [action1, action2]);
   });
 
@@ -91,8 +91,8 @@ void main() {
 
     final notifier = container.read(undoServiceProvider.notifier);
     await notifier.init();
-    notifier.pushAction(action1);
-    notifier.pushAction(action2);
+    await notifier.pushAction(action1);
+    await notifier.pushAction(action2);
 
     await notifier.undo();
     expect(container.read(undoServiceProvider), [action1]);
@@ -126,8 +126,8 @@ void main() {
 
     final notifier = container.read(undoServiceProvider.notifier);
     await notifier.init();
-    notifier.pushAction(action1);
-    notifier.pushAction(action2);
+    await notifier.pushAction(action1);
+    await notifier.pushAction(action2);
 
     await notifier.undo(actionId: '1');
     expect(container.read(undoServiceProvider), [action2]);
@@ -154,7 +154,7 @@ void main() {
 
     final notifier = container.read(undoServiceProvider.notifier);
     await notifier.init();
-    notifier.pushAction(action);
+    await notifier.pushAction(action);
 
     await notifier.undo();
     verify(mockEmailRepo.moveEmail('e1', 'INBOX')).called(1);
@@ -193,11 +193,93 @@ void main() {
 
     final notifier = container.read(undoServiceProvider.notifier);
     await notifier.init();
-    notifier.pushAction(action);
+    await notifier.pushAction(action);
 
     await notifier.undo();
 
     verify(mockEmailRepo.restoreEmails(any)).called(1);
     verify(mockEmailRepo.moveEmail('e1', 'INBOX')).called(1);
   });
+
+  test('init loads persisted history from repository', () async {
+    final persisted = UndoAction(
+      id: '99',
+      accountId: 'acc1',
+      type: UndoType.move,
+      emailIds: ['e99'],
+      sourceMailboxPath: 'INBOX',
+    );
+
+    when(
+      mockUndoRepo.getHistory(limit: anyNamed('limit')),
+    ).thenAnswer((_) async => [persisted]);
+
+    final notifier = container.read(undoServiceProvider.notifier);
+    await notifier.init();
+
+    expect(container.read(undoServiceProvider), [persisted]);
+  });
+
+  test('pushAction after restart appends to persisted history', () async {
+    final persisted = UndoAction(
+      id: '1',
+      accountId: 'acc1',
+      type: UndoType.move,
+      emailIds: ['e1'],
+      sourceMailboxPath: 'INBOX',
+    );
+    final newAction = UndoAction(
+      id: '2',
+      accountId: 'acc1',
+      type: UndoType.delete,
+      emailIds: ['e2'],
+      sourceMailboxPath: 'INBOX',
+    );
+
+    when(
+      mockUndoRepo.getHistory(limit: anyNamed('limit')),
+    ).thenAnswer((_) async => [persisted]);
+
+    final notifier = container.read(undoServiceProvider.notifier);
+    await notifier.init();
+    await notifier.pushAction(newAction);
+
+    expect(container.read(undoServiceProvider), [persisted, newAction]);
+  });
+
+  test('pushAction concurrent with init waits for init to complete', () async {
+    final persisted = UndoAction(
+      id: '1',
+      accountId: 'acc1',
+      type: UndoType.move,
+      emailIds: ['e1'],
+      sourceMailboxPath: 'INBOX',
+    );
+    final raced = UndoAction(
+      id: '2',
+      accountId: 'acc1',
+      type: UndoType.delete,
+      emailIds: ['e2'],
+      sourceMailboxPath: 'INBOX',
+    );
+
+    // Simulate slow DB load
+    when(
+      mockUndoRepo.getHistory(limit: anyNamed('limit')),
+    ).thenAnswer(
+      (_) => Future.delayed(
+        const Duration(milliseconds: 10),
+        () => [persisted],
+      ),
+    );
+
+    final notifier = container.read(undoServiceProvider.notifier);
+    final initFuture = notifier.init();
+    // pushAction issued before init completes — it must still see persisted history
+    final pushFuture = notifier.pushAction(raced);
+
+    await Future.wait([initFuture, pushFuture]);
+
+    expect(container.read(undoServiceProvider), [persisted, raced]);
+  });
 }

test/unit/undo_service_test.mocks.dart

@@ -452,6 +452,16 @@ 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

@@ -30,6 +30,7 @@ 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 +115,9 @@ 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 {
@@ -132,6 +136,8 @@ class FakeMailboxRepository implements MailboxRepository {
   @override
   Future<Mailbox?> findMailboxByRole(String accountId, String role) async =>
       _mailboxes.where((m) => m.role == role).firstOrNull;
+  @override
+  Future<void> clearForResync(String accountId) async {}
 }
 
 class FakeEmailRepository implements EmailRepository {
@@ -279,6 +285,9 @@ class FakeEmailRepository implements EmailRepository {
 
   @override
   Future<void> retryMutation(int id) async {}
+
+  @override
+  Future<void> clearForResync(String accountId) async {}
 }
 
 // ---------------------------------------------------------------------------
@@ -373,6 +382,18 @@ 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']!,
+                  ),
+                ),
+              ),
             ],
           ),
         ],

test/widget/search_screen_test.dart

@@ -0,0 +1,182 @@
+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()),
+          ],
+        ),
+      );
+      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()),
+          ],
+        ),
+      );
+      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()),
+          ],
+        ),
+      );
+      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]),
+            ),
+          ],
+        ),
+      );
+      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()),
+          ],
+        ),
+      );
+      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]),
+            ),
+          ],
+        ),
+      );
+      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();
+
+      expect(find.text('Found email'), findsNothing);
+      expect(find.text('Type 3+ characters to search'), 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);
+    });
+  });
+}