feat: add combined inbox as the default startup view

Creates a Combined Inbox that shows threads from the INBOX mailbox of
every account, sorted by date. On first launch the app opens here; if
no accounts exist yet it redirects to the account list automatically.

- EmailRepository: add observeAllInboxThreads() — JOINs threads with
  mailboxes on role='inbox', covering both IMAP and JMAP accounts
- di.dart: add allAccountsProvider (StreamProvider for all accounts)
- CombinedInboxScreen: thread list with swipe-to-archive/delete, pull-
  to-refresh, load-more pagination, per-account name label, compose FAB,
  and a drawer linking to individual account mailboxes
- router.dart: add /inbox route; change initialLocation to /inbox
- Update all test fakes and mocks for the new abstract method

Closes #376

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

lib/core/repositories/email_repository.dart

@@ -15,6 +15,10 @@ abstract class EmailRepository {
     int limit = 50,
   });
 
+  /// Returns threads from the INBOX of every account, sorted by latest date.
+  /// Inbox mailboxes are matched by role = 'inbox'.
+  Stream<List<EmailThread>> observeAllInboxThreads({int limit = 50});
+
   /// Returns all emails belonging to [threadId] in [mailboxPath].
   Stream<List<Email>> observeEmailsInThread(
     String accountId,

lib/data/repositories/email_repository_impl.dart

@@ -95,6 +95,26 @@ class EmailRepositoryImpl implements EmailRepository {
         .map((rows) => rows.map(_threadRowToModel).toList());
   }
 
+  @override
+  Stream<List<model.EmailThread>> observeAllInboxThreads({int limit = 50}) {
+    final query = _db.select(_db.threads).join([
+      innerJoin(
+        _db.mailboxes,
+        _db.mailboxes.accountId.equalsExp(_db.threads.accountId) &
+            _db.mailboxes.path.equalsExp(_db.threads.mailboxPath),
+      ),
+    ]);
+    query
+      ..where(_db.mailboxes.role.equals('inbox'))
+      ..orderBy([OrderingTerm.desc(_db.threads.latestDate)])
+      ..limit(limit);
+    return query.watch().map(
+          (rows) => rows
+              .map((row) => _threadRowToModel(row.readTable(_db.threads)))
+              .toList(),
+        );
+  }
+
   model.EmailThread _threadRowToModel(ThreadRow row) {
     List<model.EmailAddress> parseAddresses(String json) {
       final list = jsonDecode(json) as List<dynamic>;

lib/di.dart

@@ -239,6 +239,10 @@ class EmailDetailNotifier extends AsyncNotifier<(Email?, EmailBody)> {
   }
 }
 
+final allAccountsProvider = StreamProvider<List<model.Account>>((ref) {
+  return ref.watch(accountRepositoryProvider).observeAccounts();
+});
+
 final accountByIdProvider =
     StreamProvider.autoDispose.family<model.Account?, String>((ref, accountId) {
   return ref.watch(accountRepositoryProvider).observeAccounts().map(

lib/ui/router.dart

@@ -4,6 +4,7 @@ import 'package:sharedinbox/core/models/sieve_script.dart';
 
 import 'package:sharedinbox/ui/screens/about_screen.dart';
 import 'package:sharedinbox/ui/screens/account_list_screen.dart';
+import 'package:sharedinbox/ui/screens/combined_inbox_screen.dart';
 import 'package:sharedinbox/ui/screens/account_receive_screen.dart';
 import 'package:sharedinbox/ui/screens/account_send_screen.dart';
 import 'package:sharedinbox/ui/screens/add_account_screen.dart';
@@ -24,11 +25,15 @@ import 'package:sharedinbox/ui/screens/user_preferences_screen.dart';
 import 'package:sharedinbox/ui/widgets/undo_shell.dart';
 
 final router = GoRouter(
-  initialLocation: '/accounts',
+  initialLocation: '/inbox',
   routes: [
     ShellRoute(
       builder: (ctx, state, child) => UndoShell(child: child),
       routes: [
+        GoRoute(
+          path: '/inbox',
+          builder: (ctx, state) => const CombinedInboxScreen(),
+        ),
         GoRoute(
           path: '/accounts',
           builder: (ctx, state) => const AccountListScreen(),

lib/ui/screens/combined_inbox_screen.dart

@@ -0,0 +1,393 @@
+import 'dart:async';
+
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:go_router/go_router.dart';
+import 'package:intl/intl.dart';
+
+import 'package:sharedinbox/core/models/account.dart';
+import 'package:sharedinbox/core/models/email.dart';
+import 'package:sharedinbox/core/models/undo_action.dart';
+import 'package:sharedinbox/di.dart';
+
+final _dateFmt = DateFormat('MMM d');
+final _formattedDates = <int, String>{};
+
+int _dayKey(DateTime dt) => dt.year * 10000 + dt.month * 100 + dt.day;
+
+String _fmtDate(DateTime dt) =>
+    _formattedDates[_dayKey(dt)] ??= _dateFmt.format(dt);
+
+class CombinedInboxScreen extends ConsumerStatefulWidget {
+  const CombinedInboxScreen({super.key});
+
+  @override
+  ConsumerState<CombinedInboxScreen> createState() =>
+      _CombinedInboxScreenState();
+}
+
+class _CombinedInboxScreenState extends ConsumerState<CombinedInboxScreen> {
+  static const _pageSize = 50;
+  int _limit = _pageSize;
+
+  @override
+  Widget build(BuildContext context) {
+    final accountsAsync = ref.watch(allAccountsProvider);
+
+    return accountsAsync.when(
+      loading: () => const Scaffold(
+        body: Center(child: CircularProgressIndicator()),
+      ),
+      error: (e, _) => Scaffold(
+        body: Center(child: Text('Error: $e')),
+      ),
+      data: (accounts) {
+        if (accounts.isEmpty) {
+          WidgetsBinding.instance.addPostFrameCallback((_) {
+            if (context.mounted) context.go('/accounts');
+          });
+          return const Scaffold(
+            body: Center(child: CircularProgressIndicator()),
+          );
+        }
+
+        final accountNames = {
+          for (final a in accounts) a.id: a.displayName,
+        };
+        final showAccount = accounts.length > 1;
+
+        return Scaffold(
+          appBar: _buildAppBar(accounts),
+          drawer: _buildDrawer(context, accounts),
+          body: _buildBody(accountNames, showAccount),
+          floatingActionButton: FloatingActionButton(
+            onPressed: () => context.push('/compose'),
+            child: const Icon(Icons.edit),
+          ),
+        );
+      },
+    );
+  }
+
+  PreferredSizeWidget _buildAppBar(List<Account> accounts) {
+    return AppBar(
+      title: const Text('Combined Inbox'),
+      actions: [
+        IconButton(
+          icon: const Icon(Icons.search),
+          tooltip: 'Search',
+          onPressed: () => context.push('/search'),
+        ),
+        IconButton(
+          icon: const Icon(Icons.sync),
+          tooltip: 'Sync all',
+          onPressed: () {
+            for (final a in accounts) {
+              ref.read(syncManagerProvider).syncNow(a.id);
+            }
+          },
+        ),
+      ],
+    );
+  }
+
+  Widget _buildDrawer(BuildContext context, List<Account> accounts) {
+    return Drawer(
+      child: ListView(
+        padding: EdgeInsets.zero,
+        children: [
+          const DrawerHeader(
+            decoration: BoxDecoration(color: Colors.blueGrey),
+            child: Text(
+              'sharedinbox.de',
+              style: TextStyle(color: Colors.white, fontSize: 24),
+            ),
+          ),
+          ListTile(
+            leading: const Icon(Icons.manage_accounts),
+            title: const Text('Accounts'),
+            onTap: () {
+              Navigator.pop(context);
+              context.go('/accounts');
+            },
+          ),
+          ListTile(
+            leading: const Icon(Icons.person_add),
+            title: const Text('Add account'),
+            onTap: () {
+              Navigator.pop(context);
+              unawaited(context.push('/accounts/add'));
+            },
+          ),
+          const Divider(),
+          for (final account in accounts)
+            ListTile(
+              leading: const Icon(Icons.inbox),
+              title: Text(account.displayName),
+              subtitle: Text(account.email),
+              onTap: () {
+                Navigator.pop(context);
+                unawaited(context.push('/accounts/${account.id}/mailboxes'));
+              },
+            ),
+          const Divider(),
+          ListTile(
+            leading: const Icon(Icons.settings),
+            title: const Text('Preferences'),
+            onTap: () {
+              Navigator.pop(context);
+              unawaited(context.push('/accounts/preferences'));
+            },
+          ),
+          ListTile(
+            leading: const Icon(Icons.history),
+            title: const Text('Undo Log'),
+            onTap: () {
+              Navigator.pop(context);
+              unawaited(context.push('/accounts/undo-log'));
+            },
+          ),
+          ListTile(
+            leading: const Icon(Icons.info_outline),
+            title: const Text('About'),
+            onTap: () {
+              Navigator.pop(context);
+              unawaited(context.push('/accounts/about'));
+            },
+          ),
+        ],
+      ),
+    );
+  }
+
+  Widget _buildBody(Map<String, String> accountNames, bool showAccount) {
+    final emailRepo = ref.watch(emailRepositoryProvider);
+    return RefreshIndicator(
+      onRefresh: () async {
+        final accounts = ref.read(allAccountsProvider).value ?? [];
+        for (final a in accounts) {
+          ref.read(syncManagerProvider).syncNow(a.id);
+        }
+      },
+      child: StreamBuilder<List<EmailThread>>(
+        stream: emailRepo.observeAllInboxThreads(limit: _limit),
+        builder: (ctx, snap) {
+          if (!snap.hasData) {
+            return const Center(child: CircularProgressIndicator());
+          }
+          final threads = snap.data!;
+          if (threads.isEmpty) {
+            return ListView(
+              children: const [
+                SizedBox(
+                  height: 300,
+                  child: Center(child: Text('No emails')),
+                ),
+              ],
+            );
+          }
+          return _buildThreadList(threads, accountNames, showAccount);
+        },
+      ),
+    );
+  }
+
+  Widget _buildThreadList(
+    List<EmailThread> threads,
+    Map<String, String> accountNames,
+    bool showAccount,
+  ) {
+    final hasMore = threads.length == _limit;
+    return ListView.builder(
+      itemCount: threads.length + (hasMore ? 1 : 0),
+      itemBuilder: (ctx, i) {
+        if (i == threads.length) {
+          return TextButton(
+            onPressed: () => setState(() => _limit += _pageSize),
+            child: const Text('Load more'),
+          );
+        }
+        return _buildThreadTile(ctx, threads[i], accountNames, showAccount);
+      },
+    );
+  }
+
+  Widget _buildThreadTile(
+    BuildContext ctx,
+    EmailThread t,
+    Map<String, String> accountNames,
+    bool showAccount,
+  ) {
+    final senderNames =
+        t.participants.map((a) => a.name ?? a.email).take(3).join(', ');
+
+    final tile = ListTile(
+      leading: Icon(
+        t.hasUnread ? Icons.mail : Icons.mail_outline,
+        color: t.hasUnread ? Theme.of(ctx).colorScheme.primary : null,
+      ),
+      title: Row(
+        children: [
+          Expanded(
+            child: Text(
+              senderNames.isEmpty ? '(unknown)' : senderNames,
+              style: t.hasUnread
+                  ? const TextStyle(fontWeight: FontWeight.bold)
+                  : null,
+              overflow: TextOverflow.ellipsis,
+            ),
+          ),
+          if (t.messageCount > 1)
+            Padding(
+              padding: const EdgeInsets.only(left: 4),
+              child: Text(
+                '[${t.messageCount}]',
+                style: Theme.of(ctx).textTheme.bodySmall,
+              ),
+            ),
+        ],
+      ),
+      subtitle: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          Text(
+            t.subject ?? '(no subject)',
+            maxLines: 1,
+            overflow: TextOverflow.ellipsis,
+            style: t.hasUnread
+                ? const TextStyle(fontWeight: FontWeight.bold)
+                : null,
+          ),
+          if (t.preview != null && t.preview!.isNotEmpty)
+            Text(
+              t.preview!,
+              maxLines: 1,
+              overflow: TextOverflow.ellipsis,
+              style: Theme.of(ctx).textTheme.bodySmall,
+            ),
+          if (showAccount)
+            Text(
+              accountNames[t.accountId] ?? t.accountId,
+              maxLines: 1,
+              overflow: TextOverflow.ellipsis,
+              style: Theme.of(ctx).textTheme.bodySmall?.copyWith(
+                    color: Theme.of(ctx).colorScheme.primary,
+                  ),
+            ),
+        ],
+      ),
+      trailing: Row(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          if (t.isFlagged)
+            const Icon(Icons.star, color: Colors.amber, size: 16),
+          const SizedBox(width: 4),
+          Text(
+            _fmtDate(t.latestDate),
+            style: Theme.of(ctx).textTheme.bodySmall,
+          ),
+        ],
+      ),
+      onTap: t.messageCount > 1
+          ? () => context.push(
+                '/accounts/${t.accountId}/mailboxes'
+                '/${Uri.encodeComponent(t.mailboxPath)}'
+                '/threads/${Uri.encodeComponent(t.threadId)}',
+              )
+          : () => context.push(
+                '/accounts/${t.accountId}/mailboxes'
+                '/${Uri.encodeComponent(t.mailboxPath)}'
+                '/emails/${Uri.encodeComponent(t.latestEmailId)}',
+              ),
+    );
+
+    return Dismissible(
+      key: ValueKey('${t.accountId}:${t.threadId}'),
+      background: _swipeBackground(
+        alignment: Alignment.centerLeft,
+        color: Colors.green,
+        icon: Icons.archive,
+        label: 'Archive',
+      ),
+      secondaryBackground: _swipeBackground(
+        alignment: Alignment.centerRight,
+        color: Colors.red,
+        icon: Icons.delete,
+        label: 'Delete',
+      ),
+      onDismissed: (direction) => unawaited(_onSwipeDismissed(t, direction)),
+      child: tile,
+    );
+  }
+
+  Future<void> _onSwipeDismissed(
+    EmailThread t,
+    DismissDirection direction,
+  ) async {
+    final repo = ref.read(emailRepositoryProvider);
+
+    final originalEmails = (await Future.wait(
+      t.emailIds.map((id) => repo.getEmail(id)),
+    ))
+        .whereType<Email>()
+        .toList();
+
+    if (direction == DismissDirection.startToEnd) {
+      final archive = await ref
+          .read(mailboxRepositoryProvider)
+          .findMailboxByRole(t.accountId, 'archive');
+      if (!mounted || archive == null) return;
+
+      for (final id in t.emailIds) {
+        await repo.moveEmail(id, archive.path);
+      }
+      final action = UndoAction(
+        id: DateTime.now().toIso8601String(),
+        accountId: t.accountId,
+        type: UndoType.move,
+        emailIds: t.emailIds,
+        sourceMailboxPath: t.mailboxPath,
+        destinationMailboxPath: archive.path,
+        originalEmails: originalEmails,
+      );
+      unawaited(ref.read(undoServiceProvider.notifier).pushAction(action));
+      return;
+    }
+
+    String? lastDestPath;
+    for (final id in t.emailIds) {
+      lastDestPath = await repo.deleteEmail(id);
+    }
+    final action = UndoAction(
+      id: DateTime.now().toIso8601String(),
+      accountId: t.accountId,
+      type: UndoType.delete,
+      emailIds: t.emailIds,
+      sourceMailboxPath: t.mailboxPath,
+      destinationMailboxPath: lastDestPath,
+      originalEmails: originalEmails,
+    );
+    unawaited(ref.read(undoServiceProvider.notifier).pushAction(action));
+  }
+
+  Widget _swipeBackground({
+    required AlignmentGeometry alignment,
+    required Color color,
+    required IconData icon,
+    required String label,
+  }) {
+    return Container(
+      color: color,
+      alignment: alignment,
+      padding: const EdgeInsets.symmetric(horizontal: 20),
+      child: Row(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          Icon(icon, color: Colors.white),
+          const SizedBox(width: 8),
+          Text(label, style: const TextStyle(color: Colors.white)),
+        ],
+      ),
+    );
+  }
+}

test/backend/account_sync_manager_test.dart

@@ -186,6 +186,10 @@ class _FakeEmails implements EmailRepository {
   }) =>
       Stream.value([]);
 
+  @override
+  Stream<List<EmailThread>> observeAllInboxThreads({int limit = 50}) =>
+      Stream.value([]);
+
   @override
   Stream<List<Email>> observeEmailsInThread(String a, String m, String t) =>
       Stream.value([]);

test/unit/account_sync_manager_test.dart

@@ -81,6 +81,9 @@ class FakeEmailRepository implements EmailRepository {
   }) =>
       Stream.value([]);
   @override
+  Stream<List<EmailThread>> observeAllInboxThreads({int limit = 50}) =>
+      Stream.value([]);
+  @override
   Stream<List<Email>> observeEmailsInThread(String a, String m, String t) =>
       Stream.value([]);
   @override

test/unit/account_sync_manager_test.mocks.dart

@@ -287,6 +287,19 @@ class MockEmailRepository extends _i1.Mock implements _i9.EmailRepository {
         returnValue: _i5.Stream<List<_i3.EmailThread>>.empty(),
       ) as _i5.Stream<List<_i3.EmailThread>>);
 
+  @override
+  _i5.Stream<List<_i3.EmailThread>> observeAllInboxThreads({
+    int? limit = 50,
+  }) =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #observeAllInboxThreads,
+          [],
+          {#limit: limit},
+        ),
+        returnValue: _i5.Stream<List<_i3.EmailThread>>.empty(),
+      ) as _i5.Stream<List<_i3.EmailThread>>);
+
   @override
   _i5.Stream<List<_i3.Email>> observeEmailsInThread(
     String? accountId,

test/unit/reliability_runner_check_now_test.dart

@@ -103,6 +103,9 @@ class _FakeEmails implements EmailRepository {
   }) =>
       Stream.value([]);
   @override
+  Stream<List<EmailThread>> observeAllInboxThreads({int limit = 50}) =>
+      Stream.value([]);
+  @override
   Stream<List<Email>> observeEmailsInThread(String a, String m, String t) =>
       Stream.value([]);
   @override

test/unit/reliability_runner_test.dart

@@ -102,6 +102,9 @@ class _CountingEmails implements EmailRepository {
   }) =>
       Stream.value([]);
   @override
+  Stream<List<EmailThread>> observeAllInboxThreads({int limit = 50}) =>
+      Stream.value([]);
+  @override
   Stream<List<Email>> observeEmailsInThread(String a, String m, String t) =>
       Stream.value([]);
   @override

test/unit/undo_service_test.mocks.dart

@@ -109,6 +109,19 @@ class MockEmailRepository extends _i1.Mock implements _i3.EmailRepository {
         returnValue: _i4.Stream<List<_i2.EmailThread>>.empty(),
       ) as _i4.Stream<List<_i2.EmailThread>>);
 
+  @override
+  _i4.Stream<List<_i2.EmailThread>> observeAllInboxThreads({
+    int? limit = 50,
+  }) =>
+      (super.noSuchMethod(
+        Invocation.method(
+          #observeAllInboxThreads,
+          [],
+          {#limit: limit},
+        ),
+        returnValue: _i4.Stream<List<_i2.EmailThread>>.empty(),
+      ) as _i4.Stream<List<_i2.EmailThread>>);
+
   @override
   _i4.Stream<List<_i2.Email>> observeEmailsInThread(
     String? accountId,

test/widget/helpers.dart

@@ -245,6 +245,10 @@ class FakeEmailRepository implements EmailRepository {
         }).toList();
       });
 
+  @override
+  Stream<List<EmailThread>> observeAllInboxThreads({int limit = 50}) =>
+      Stream.value([]);
+
   @override
   Stream<List<Email>> observeEmailsInThread(
     String accountId,