feat(ui): harden empty workspace and shell overlays (#339)

lib/core/storage/app_settings.dart

@@ -41,6 +41,9 @@ const double kDefaultConnectionsPanelWidth = 260;
 const double kMinConnectionsPanelWidth = 180;
 const double kMaxConnectionsPanelWidth = 500;
 
+/// How many recently selected connections to surface on the empty workspace.
+const int kMaxRecentConnections = 5;
+
 /// Fixed tick marks on the interface scale slider (75% … 200%).
 const List<double> kUiScalePresets = [
   0.75,
@@ -119,6 +122,7 @@ abstract final class AppSettingsKeys {
   static const themeAnimationEnabled = 'theme_animation_enabled';
   static const uiScale = 'ui_scale';
   static const connectionsPanelWidth = 'connections_panel_width';
+  static const recentConnectionIds = 'recent_connection_ids';
   static const motionLevel = 'motion_level';
   static const updateChannel = 'update_channel';
   static const checkForUpdatesOnStartup = 'check_for_updates_on_startup';
@@ -268,6 +272,46 @@ class AppSettings {
     );
   }
 
+  /// Most recently selected connection ids (newest first).
+  Future<List<int>> getRecentConnectionIds() async {
+    final raw = await LocalDb.instance.getAppSetting(
+      AppSettingsKeys.recentConnectionIds,
+    );
+    if (raw == null || raw.isEmpty) return const [];
+    try {
+      final decoded = jsonDecode(raw);
+      if (decoded is! List) return const [];
+      final ids = <int>[];
+      for (final item in decoded) {
+        final id = item is int ? item : int.tryParse('$item');
+        if (id != null && id > 0 && !ids.contains(id)) {
+          ids.add(id);
+        }
+        if (ids.length >= kMaxRecentConnections) break;
+      }
+      return ids;
+    } catch (_) {
+      return const [];
+    }
+  }
+
+  /// Records [connectionId] as the most recently selected connection.
+  Future<void> recordRecentConnection(int connectionId) async {
+    if (connectionId <= 0) return;
+    final current = await getRecentConnectionIds();
+    final next = <int>[
+      connectionId,
+      ...current.where((id) => id != connectionId),
+    ];
+    if (next.length > kMaxRecentConnections) {
+      next.removeRange(kMaxRecentConnections, next.length);
+    }
+    await LocalDb.instance.setAppSetting(
+      AppSettingsKeys.recentConnectionIds,
+      jsonEncode(next),
+    );
+  }
+
   /// Max SQL history rows kept per connection + database (oldest trimmed).
   Future<int> getSqlHistoryMaxEntries() async {
     final v = await LocalDb.instance.getAppSetting(

lib/features/extensions/extension_table_view.dart

@@ -177,13 +177,13 @@ class _ExtensionTableViewState extends material.State<ExtensionTableView> {
   }
 
   Future<void> _openDdlDialog() async {
-    material.showDialog<void>(
+    unawaited(showAppDialog<void>(
       context: context,
       barrierDismissible: false,
       builder: (ctx) => const material.Center(
         child: material.CircularProgressIndicator(),
       ),
-    );
+    ));
 
     try {
       final meta = await ExtensionDriverSession.instance.getObjectMetadata(
@@ -198,7 +198,7 @@ class _ExtensionTableViewState extends material.State<ExtensionTableView> {
           ? meta.ddl!
           : '-- No DDL metadata returned by extension driver for ${widget.tableName}\nSELECT * FROM $_qualifiedName LIMIT 10;';
 
-      await material.showDialog<void>(
+      await showAppDialog<void>(
         context: context,
         builder: (ctx) => material.AlertDialog(
           title: material.Text(

lib/features/main_screen/main_screen.dart

@@ -44,6 +44,10 @@ class _MainScreenState extends State<MainScreen> {
 
   void _onConnectionSelected(ConnectionRow connection) {
     _workspace.value = _workspace.value.selectConnection(connection);
+    final id = connection.id;
+    if (id != null) {
+      unawaited(AppSettings.instance.recordRecentConnection(id));
+    }
   }
 
   void _onPostgresObjectSelected(
@@ -264,6 +268,7 @@ class _MainScreenState extends State<MainScreen> {
                         onRequestNewConnectionFromUrl:
                             _onNewDatabaseConnectionFromUrl,
                         onRequestOpenSqlite: _openSqliteFromHero,
+                        onOpenConnection: _onConnectionSelected,
                       ),
                     ),
                   ],
@@ -295,6 +300,7 @@ class _MainContentSplit extends StatefulWidget {
     required this.onRequestNewConnection,
     required this.onRequestNewConnectionFromUrl,
     required this.onRequestOpenSqlite,
+    required this.onOpenConnection,
   });
 
   final GlobalKey<ConnectionsPanelState> connectionsPanelKey;
@@ -331,6 +337,7 @@ class _MainContentSplit extends StatefulWidget {
   final VoidCallback onRequestNewConnection;
   final VoidCallback onRequestNewConnectionFromUrl;
   final VoidCallback onRequestOpenSqlite;
+  final void Function(ConnectionRow) onOpenConnection;
 
   @override
   State<_MainContentSplit> createState() => _MainContentSplitState();
@@ -442,6 +449,7 @@ class _MainContentSplitState extends State<_MainContentSplit> {
                       onRequestNewConnectionFromUrl:
                           widget.onRequestNewConnectionFromUrl,
                       onRequestOpenSqlite: widget.onRequestOpenSqlite,
+                      onOpenConnection: widget.onOpenConnection,
                     );
                   },
                 ),