diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index fac4a9a6..44af14e4 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -40,6 +40,36 @@ jobs:
             echo "Tag $RAW matches pubspec semver $VER."
           fi
 
+  # End-to-end scenarios (test/e2e) must pass before a release is published.
+  e2e:
+    name: E2E tests
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Flutter
+        uses: subosito/flutter-action@v2
+        with:
+          flutter-version: '3.47.1'
+          channel: 'stable'
+          cache: true
+
+      - name: Install Linux dependencies
+        timeout-minutes: 8
+        run: |
+          APT="-o Acquire::Retries=3 -o Acquire::http::Timeout=20 -o Acquire::https::Timeout=20"
+          sudo apt-get $APT update
+          # bubblewrap runs the extension sandbox scenario; without it it skips.
+          sudo apt-get $APT install -y libsecret-1-dev bubblewrap
+          sudo sysctl -w kernel.apparmor_restrict_unprivileged_userns=0
+
+      - name: Get dependencies
+        run: flutter pub get
+
+      - name: Run E2E tests
+        run: flutter test test/e2e
+
   build-windows:
     name: Build Windows
     runs-on: windows-latest
@@ -436,7 +466,7 @@ jobs:
 
   publish:
     name: Publish GitHub Release
-    needs: [build-windows, build-linux, build-macos, build-ext-tester]
+    needs: [e2e, build-windows, build-linux, build-macos, build-ext-tester]
     runs-on: ubuntu-latest
     outputs:
       version: ${{ needs.build-windows.outputs.version }}
diff --git a/lib/core/database/mongodb_service.dart b/lib/core/database/mongodb_service.dart
index fa282dcb..82ad0e04 100644
--- a/lib/core/database/mongodb_service.dart
+++ b/lib/core/database/mongodb_service.dart
@@ -1,3 +1,4 @@
+import 'package:flutter/foundation.dart' show visibleForTesting;
 import 'package:mongo_dart/mongo_dart.dart';
 
 import '../storage/local_db.dart';
@@ -31,7 +32,20 @@ void _throwIfMongoWriteFailed(
 /// Service for managing MongoDB connections.
 class MongoService {
   MongoService._();
-  static final MongoService instance = MongoService._();
+
+  /// A service a test subclasses to answer without a server.
+  @visibleForTesting
+  MongoService.forTest();
+
+  static final MongoService _real = MongoService._();
+  static MongoService _instance = _real;
+
+  static MongoService get instance => _instance;
+
+  /// Replaces [instance] in tests; null puts the real service back.
+  @visibleForTesting
+  static set instanceForTest(MongoService? service) =>
+      _instance = service ?? _real;
 
   final Map<int, MongoConnection> _connections = {};
 
diff --git a/test/e2e/04_nosql_workspaces/e2e_mongo_explorer_and_crud_test.dart b/test/e2e/04_nosql_workspaces/e2e_mongo_explorer_and_crud_test.dart
new file mode 100644
index 00000000..b2189023
--- /dev/null
+++ b/test/e2e/04_nosql_workspaces/e2e_mongo_explorer_and_crud_test.dart
@@ -0,0 +1,223 @@
+import 'package:flutter/material.dart' as material;
+import 'package:flutter_test/flutter_test.dart';
+import 'package:querya_desktop/core/database/mongodb_connection.dart';
+import 'package:querya_desktop/core/database/mongodb_service.dart';
+import 'package:querya_desktop/features/mongodb/mongo_add_document_dialog.dart';
+import 'package:querya_desktop/features/mongodb/mongo_collections_view.dart';
+import 'package:querya_desktop/features/mongodb/mongo_documents_view.dart';
+
+import '../../support/querya_theme_test_shell.dart';
+
+const _timeout = Timeout(Duration(seconds: 60));
+
+/// A connection that lists two collections and never opens a socket.
+class _Connection extends MongoConnection {
+  _Connection() : super(id: 11, name: 'shop-mongo', host: 'localhost');
+
+  @override
+  Future<List<String>> listCollections(String databaseName) async =>
+      const ['orders', 'users'];
+}
+
+/// Documents in memory, with every write recorded.
+class _FakeMongo extends MongoService {
+  _FakeMongo() : super.forTest();
+
+  final docs = <Map<String, dynamic>>[
+    {'_id': 1, 'name': 'ann', 'city': 'Berlin'},
+    {'_id': 2, 'name': 'bob', 'city': 'Paris'},
+  ];
+  final inserted = <Map<String, dynamic>>[];
+  final updates = <(Map<String, dynamic>, Map<String, dynamic>)>[];
+  final deletes = <Map<String, dynamic>>[];
+  var nextId = 3;
+
+  @override
+  Future<List<Map<String, dynamic>>> find(
+    MongoConnection connection,
+    String database,
+    String collection, {
+    Map<String, dynamic>? filter,
+    Map<String, dynamic>? projection,
+    Map<String, dynamic>? sort,
+    int? limit,
+    int? skip,
+  }) async =>
+      [for (final d in docs) Map<String, dynamic>.of(d)];
+
+  @override
+  Future<int> countDocuments(
+    MongoConnection connection,
+    String database,
+    String collection, {
+    Map<String, dynamic>? filter,
+  }) async =>
+      docs.length;
+
+  @override
+  Future<Map<String, dynamic>> insertDocument(
+    MongoConnection connection,
+    String database,
+    String collection,
+    Map<String, dynamic> document,
+  ) async {
+    inserted.add(document);
+    docs.add({'_id': nextId++, ...document});
+    return document;
+  }
+
+  @override
+  Future<void> updateDocument(
+    MongoConnection connection,
+    String database,
+    String collection,
+    Map<String, dynamic> filter,
+    Map<String, dynamic> update,
+  ) async {
+    updates.add((filter, update));
+    final doc = docs.firstWhere((d) => d['_id'] == filter['_id']);
+    doc.addAll((update[r'$set'] as Map).cast<String, dynamic>());
+  }
+
+  @override
+  Future<void> deleteDocument(
+    MongoConnection connection,
+    String database,
+    String collection,
+    Map<String, dynamic> filter,
+  ) async {
+    deletes.add(filter);
+    docs.removeWhere((d) => d['_id'] == filter['_id']);
+  }
+}
+
+/// The sidebar's collection list, and the documents of the one picked.
+class _Explorer extends material.StatefulWidget {
+  const _Explorer(this.connection);
+
+  final MongoConnection connection;
+
+  @override
+  material.State<_Explorer> createState() => _ExplorerState();
+}
+
+class _ExplorerState extends material.State<_Explorer> {
+  String? _collection;
+
+  @override
+  material.Widget build(material.BuildContext context) {
+    final collection = _collection;
+    return material.Scaffold(
+      body: collection == null
+          ? MongoCollectionsView(
+              connection: widget.connection,
+              database: 'shop',
+              onCollectionTap: (name) => setState(() => _collection = name),
+            )
+          : MongoDocumentsView(
+              connection: widget.connection,
+              database: 'shop',
+              collection: collection,
+              initialViewMode: MongoDocumentsViewMode.cards,
+            ),
+    );
+  }
+}
+
+void main() {
+  late _FakeMongo mongo;
+
+  setUp(() {
+    mongo = _FakeMongo();
+    MongoService.instanceForTest = mongo;
+  });
+  tearDown(() => MongoService.instanceForTest = null);
+
+  Future<void> settle(WidgetTester t) async {
+    for (var i = 0; i < 5; i++) {
+      await t.pump(const Duration(milliseconds: 100));
+    }
+  }
+
+  testWidgets(
+      'collections open into documents; add, edit and delete a document (#1052)',
+      timeout: _timeout, (tester) async {
+    await tester.binding.setSurfaceSize(const material.Size(1300, 900));
+    addTearDown(() => tester.binding.setSurfaceSize(null));
+    await tester.pumpWidget(queryaThemeTestShell(child: _Explorer(_Connection())));
+    await settle(tester);
+
+    // The collections of the database, and a tap opens one.
+    expect(find.text('orders'), findsOneWidget);
+    expect(find.text('users'), findsOneWidget);
+    await tester.tap(find.text('orders'));
+    await settle(tester);
+    expect(find.byType(MongoDocumentsView), findsOneWidget);
+    // One card per document.
+    final cards = find.byIcon(material.Icons.description_rounded);
+    expect(cards, findsNWidgets(2));
+
+    // Add a document through the dialog.
+    await tester.tap(find.text('Add Document'));
+    await settle(tester);
+    await tester.enterText(
+      find.descendant(
+        of: find.byType(MongoAddDocumentDialog),
+        matching: find.byType(material.EditableText),
+      ),
+      '{"name": "cid", "city": "Rome"}',
+    );
+    await tester.pump();
+    await tester.tap(find.text('Insert Document'));
+    await settle(tester);
+    expect(mongo.inserted, hasLength(1));
+    expect(mongo.inserted.single['name'], 'cid');
+    expect(cards, findsNWidgets(3), reason: 'the list reloads with the new one');
+
+    // Edit a field of the first document from its expanded card.
+    await tester.tap(find.byIcon(material.Icons.expand_more_rounded).first);
+    await settle(tester);
+    await tester.tap(find.text('name').first);
+    await settle(tester);
+    await tester.enterText(find.byType(material.EditableText).last, 'annie');
+    await tester.pump();
+    await tester.tap(find.text('Save to DB'));
+    await settle(tester);
+    expect(mongo.updates, hasLength(1));
+    expect(mongo.updates.single.$1, {'_id': 1});
+    expect(mongo.updates.single.$2, {
+      r'$set': {'name': 'annie'},
+    });
+
+    // Delete it, after confirming.
+    await tester.tap(find.byIcon(material.Icons.delete_rounded).first);
+    await settle(tester);
+    await tester.tap(find.text(
+        'I understand that this query cannot be undone and may result in permanent data loss.'));
+    await tester.pump();
+    await tester.tap(find.text('Execute Destructive Statement'));
+    await settle(tester);
+    expect(mongo.deletes, [
+      {'_id': 1},
+    ]);
+    expect(cards, findsNWidgets(2), reason: 'the list reloads without it');
+    expect(mongo.docs.map((d) => d['name']), ['bob', 'cid']);
+  });
+
+  testWidgets('cancelling the delete keeps the document (#1052)',
+      timeout: _timeout, (tester) async {
+    await tester.binding.setSurfaceSize(const material.Size(1300, 900));
+    addTearDown(() => tester.binding.setSurfaceSize(null));
+    await tester.pumpWidget(queryaThemeTestShell(child: _Explorer(_Connection())));
+    await settle(tester);
+    await tester.tap(find.text('orders'));
+    await settle(tester);
+
+    await tester.tap(find.byIcon(material.Icons.delete_rounded).first);
+    await settle(tester);
+    await tester.tap(find.text('Cancel').last);
+    await settle(tester);
+    expect(mongo.deletes, isEmpty);
+    expect(mongo.docs, hasLength(2));
+  });
+}
diff --git a/test/e2e/06_shell_theme_and_command_palette/e2e_app_lifecycle_and_shutdown_test.dart b/test/e2e/06_shell_theme_and_command_palette/e2e_app_lifecycle_and_shutdown_test.dart
new file mode 100644
index 00000000..fd89d330
--- /dev/null
+++ b/test/e2e/06_shell_theme_and_command_palette/e2e_app_lifecycle_and_shutdown_test.dart
@@ -0,0 +1,89 @@
+import 'dart:io';
+
+import 'package:flutter/material.dart' as material;
+import 'package:flutter_test/flutter_test.dart';
+import 'package:querya_desktop/app/app_lifecycle_cleanup.dart';
+import 'package:querya_desktop/core/database/sqlite_service.dart';
+import 'package:querya_desktop/core/mcp/mcp_server_controller.dart';
+import 'package:querya_desktop/core/storage/app_settings.dart';
+import 'package:querya_desktop/core/storage/local_db.dart';
+import 'package:querya_desktop/features/main_screen/main_screen.dart';
+
+import '../../support/querya_theme_test_shell.dart';
+import '../helpers/e2e_app_harness.dart';
+
+/// #1053: closing the window stops the MCP server and closes pooled database
+/// sessions; settings written in one run are there in the next.
+void main() {
+  final app = E2eAppHarness(prefix: 'querya_e2e_lifecycle_');
+  setUpAll(app.setUpAll);
+  tearDownAll(app.tearDownAll);
+
+  Future<void> pumpApp(WidgetTester tester) async {
+    await tester.binding.setSurfaceSize(const material.Size(1400, 900));
+    addTearDown(() => tester.binding.setSurfaceSize(null));
+    await tester.pumpWidget(queryaThemeTestShell(
+      child: const AppLifecycleCleanup(
+        child: material.SizedBox(width: 1400, height: 900, child: MainScreen()),
+      ),
+    ));
+    await E2eAppHarness.settle(tester);
+  }
+
+  testWidgets('closing the app stops MCP and closes pooled sessions',
+      (tester) async {
+    final path = '${app.dataDir.path}/lifecycle.db';
+    File(path).createSync();
+    final row = ConnectionRow(
+      id: 501,
+      type: 'sqlite',
+      name: 'Lifecycle',
+      host: path,
+      createdAt: DateTime.utc(2026).toIso8601String(),
+    );
+    final lease =
+        (await tester.runAsync(() => SqliteService.instance.acquire(row)))!;
+    expect(lease.connection.isConnected, isTrue);
+
+    final mcp = McpServerController.instance;
+    await tester.runAsync(mcp.start);
+    expect(mcp.status.value.running, isTrue);
+    expect(mcp.endpointFile.existsSync(), isTrue);
+
+    await pumpApp(tester);
+
+    // Close the window: the cleanup runs as the app goes away.
+    await tester.pumpWidget(const material.SizedBox.shrink());
+    for (var i = 0;
+        i < 80 && (mcp.status.value.running || lease.connection.isConnected);
+        i++) {
+      await tester.runAsync(
+          () => Future<void>.delayed(const Duration(milliseconds: 25)));
+      await tester.pump(const Duration(milliseconds: 50));
+    }
+
+    expect(mcp.status.value.running, isFalse);
+    expect(mcp.endpointFile.existsSync(), isFalse,
+        reason: 'no client may find a dead endpoint');
+    expect(lease.connection.isConnected, isFalse);
+    lease.release();
+    await app.close(tester);
+  });
+
+  testWidgets('a setting written in one run is read in the next',
+      (tester) async {
+    await pumpApp(tester);
+    await tester
+        .runAsync(() => AppSettings.instance.setExportCurrentTheme(true));
+    await tester.pumpWidget(const material.SizedBox.shrink());
+    await tester.pump();
+
+    await pumpApp(tester);
+    final value = await tester
+        .runAsync(() => AppSettings.instance.getExportCurrentTheme());
+    expect(value, isTrue);
+    await tester
+        .runAsync(() => AppSettings.instance.setExportCurrentTheme(false));
+    await app.close(tester);
+  });
+}
diff --git a/test/e2e/06_shell_theme_and_command_palette/e2e_theme_import_and_morphing_test.dart b/test/e2e/06_shell_theme_and_command_palette/e2e_theme_import_and_morphing_test.dart
new file mode 100644
index 00000000..1a3f9edb
--- /dev/null
+++ b/test/e2e/06_shell_theme_and_command_palette/e2e_theme_import_and_morphing_test.dart
@@ -0,0 +1,93 @@
+import 'package:flutter/material.dart' as material;
+import 'package:flutter_test/flutter_test.dart';
+import 'package:querya_desktop/core/theme/parser/querya_theme_from_vscode.dart';
+import 'package:querya_desktop/core/theme/parser/vscode_theme_manifest.dart';
+import 'package:querya_desktop/core/theme/querya_theme.dart';
+import 'package:querya_desktop/core/theme/querya_theme_scope.dart';
+import 'package:querya_desktop/features/connections/connections_panel.dart';
+import 'package:querya_desktop/features/main_screen/main_screen.dart';
+
+import '../../support/querya_theme_test_shell.dart';
+import '../helpers/e2e_app_harness.dart';
+
+/// A VS Code theme as users paste it: comments and trailing commas (JSONC).
+const _jsonc = '''
+{
+  // Exported from VS Code.
+  "name": "E2E Night",
+  "type": "dark",
+  "colors": {
+    "editor.background": "#101820",
+    "sideBar.background": "#0b1016", // the sidebar
+    "foreground": "#e6e6e6",
+  },
+}
+''';
+
+/// #1053: a theme imported from VS Code recolours the running app, and the
+/// switch never passes through a light frame.
+void main() {
+  final app = E2eAppHarness(prefix: 'querya_e2e_theme_');
+  setUpAll(app.setUpAll);
+  tearDownAll(app.tearDownAll);
+
+  QueryaTheme themeIn(WidgetTester t) =>
+      QueryaThemeScope.of(t.element(find.byType(ConnectionsPanel)));
+
+  testWidgets('an imported JSONC theme recolours the running app',
+      (tester) async {
+    final imported =
+        buildQueryaThemeFromVsCodeManifest(VsCodeThemeManifest.fromJsonString(_jsonc));
+    expect(imported.workbench.editorBackground, const material.Color(0xFF101820));
+    expect(imported.workbench.sidebarBackground, const material.Color(0xFF0B1016));
+
+    final active = material.ValueNotifier<QueryaTheme>(QueryaTheme.darkDefault);
+    addTearDown(active.dispose);
+    await tester.binding.setSurfaceSize(const material.Size(1400, 900));
+    addTearDown(() => tester.binding.setSurfaceSize(null));
+    await tester.pumpWidget(material.ValueListenableBuilder<QueryaTheme>(
+      valueListenable: active,
+      builder: (context, theme, _) => queryaThemeTestShell(
+        data: theme,
+        child: const material.SizedBox(
+            width: 1400, height: 900, child: MainScreen()),
+      ),
+    ));
+    await E2eAppHarness.settle(tester);
+    expect(themeIn(tester).workbench.sidebarBackground,
+        QueryaTheme.darkDefault.workbench.sidebarBackground);
+    final panel = tester.state(find.byType(ConnectionsPanel));
+
+    active.value = imported;
+    // Every frame of the switch stays dark: no white flash.
+    for (var i = 0; i < 30; i++) {
+      await tester.pump(const Duration(milliseconds: 16));
+      final w = themeIn(tester).workbench;
+      expect(w.sidebarBackground.computeLuminance(), lessThan(0.2),
+          reason: 'frame $i');
+      expect(w.editorBackground.computeLuminance(), lessThan(0.2),
+          reason: 'frame $i');
+    }
+    expect(themeIn(tester).workbench.sidebarBackground,
+        const material.Color(0xFF0B1016));
+    expect(themeIn(tester).workbench.editorBackground,
+        const material.Color(0xFF101820));
+    // The app was recoloured in place, not rebuilt from scratch.
+    expect(identical(tester.state(find.byType(ConnectionsPanel)), panel), isTrue);
+    expect(tester.takeException(), isNull);
+
+    // And back to the built-in theme.
+    active.value = QueryaTheme.darkDefault;
+    await tester.pump();
+    expect(themeIn(tester).workbench.sidebarBackground,
+        QueryaTheme.darkDefault.workbench.sidebarBackground);
+    await app.close(tester);
+  });
+
+  test('a theme that is not JSON is refused with a clear error', () {
+    expect(
+      () => VsCodeThemeManifest.fromJsonString('{ "colors": '),
+      throwsA(isA<VsCodeThemeParseException>()),
+    );
+  });
+}