Small UX tweaks: tab close affordance and date quick-fill

- Show the tab close button for an open presentation tab even when it is the
  only tab.
- Double-click the date field in the presentation-info dialog to fill in
  today's date.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/widgets/app_shell.dart

@@ -550,7 +550,8 @@ class _AppTabBar extends StatelessWidget {
                     _TabChip(
                       tab: tabsState.tabs[i],
                       isActive: i == tabsState.clampedIndex,
-                      showClose: tabsState.tabs.length > 1,
+                      showClose:
+                          tabsState.tabs.length > 1 || tabsState.tabs[i].isOpen,
                       panelText: palette.panelText,
                       accent: Theme.of(context).colorScheme.secondary,
                       onTap: () => onSelect(i),

lib/widgets/dialogs/presentation_info_dialog.dart

@@ -91,6 +91,13 @@ class _PresentationInfoDialogState extends State<PresentationInfoDialog> {
     );
   }
 
+  void _setCurrentDate() {
+    final now = DateTime.now();
+    String twoDigits(int value) => value.toString().padLeft(2, '0');
+    _date.text = '${now.year}-${twoDigits(now.month)}-${twoDigits(now.day)}';
+    _date.selection = TextSelection.collapsed(offset: _date.text.length);
+  }
+
   @override
   Widget build(BuildContext context) {
     final l10n = context.l10n;
@@ -143,7 +150,12 @@ class _PresentationInfoDialogState extends State<PresentationInfoDialog> {
                     const SizedBox(width: 12),
                     SizedBox(
                       width: 120,
-                      child: _field(_date, 'Datum', 'Bijv. 2026-05-30'),
+                      child: _field(
+                        _date,
+                        'Datum',
+                        'Bijv. 2026-05-30',
+                        onDoubleTap: _setCurrentDate,
+                      ),
                     ),
                   ],
                 ),
@@ -190,9 +202,10 @@ class _PresentationInfoDialogState extends State<PresentationInfoDialog> {
     String label,
     String hint, {
     int maxLines = 1,
+    VoidCallback? onDoubleTap,
   }) {
     final l10n = context.l10n;
-    return TextField(
+    final field = TextField(
       controller: controller,
       maxLines: maxLines,
       decoration: InputDecoration(
@@ -202,5 +215,11 @@ class _PresentationInfoDialogState extends State<PresentationInfoDialog> {
         border: const OutlineInputBorder(),
       ),
     );
+    if (onDoubleTap == null) return field;
+    return GestureDetector(
+      behavior: HitTestBehavior.translucent,
+      onDoubleTap: onDoubleTap,
+      child: field,
+    );
   }
 }

test/presentation_info_dialog_test.dart

@@ -0,0 +1,33 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:ocideck/models/deck.dart';
+import 'package:ocideck/widgets/dialogs/presentation_info_dialog.dart';
+
+void main() {
+  testWidgets('double-clicking date fills in the current date', (tester) async {
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: Scaffold(
+          body: PresentationInfoDialog(deck: Deck(title: 'Test')),
+        ),
+      ),
+    );
+
+    final dateField = find.byWidgetPredicate(
+      (widget) =>
+          widget is TextField && widget.decoration?.labelText == 'Datum',
+    );
+    final now = DateTime.now();
+    String twoDigits(int value) => value.toString().padLeft(2, '0');
+    final expected =
+        '${now.year}-${twoDigits(now.month)}-${twoDigits(now.day)}';
+
+    await tester.tap(dateField);
+    await tester.pump(const Duration(milliseconds: 50));
+    await tester.tap(dateField);
+    await tester.pump(const Duration(milliseconds: 100));
+
+    final field = tester.widget<TextField>(dateField);
+    expect(field.controller!.text, expected);
+  });
+}

test/widget_test.dart

@@ -2,6 +2,10 @@ import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:ocideck/app.dart';
+import 'package:ocideck/models/deck.dart';
+import 'package:ocideck/models/slide.dart';
+import 'package:ocideck/state/tabs_provider.dart';
+import 'package:ocideck/widgets/app_shell.dart';
 
 void main() {
   testWidgets('Welcome screen shows startup logo', (WidgetTester tester) async {
@@ -16,4 +20,27 @@ void main() {
     await tester.pumpWidget(const ProviderScope(child: OciDeckApp()));
     expect(find.byIcon(Icons.settings_outlined), findsOneWidget);
   });
+
+  testWidgets('the only open presentation can be closed', (tester) async {
+    await tester.binding.setSurfaceSize(const Size(1600, 1000));
+    addTearDown(() => tester.binding.setSurfaceSize(null));
+    await tester.pumpWidget(const ProviderScope(child: OciDeckApp()));
+    final container = ProviderScope.containerOf(
+      tester.element(find.byType(AppShell)),
+    );
+    final tab = container.read(tabsProvider).current!;
+    tab.deckNotifier.loadDeck(
+      Deck(
+        title: 'Test',
+        slides: [Slide.create(SlideType.title).copyWith(title: 'Test')],
+      ),
+    );
+    await tester.pump();
+
+    expect(find.byIcon(Icons.close), findsOneWidget);
+    await tester.tap(find.byIcon(Icons.close));
+    await tester.pump();
+
+    expect(container.read(tabsProvider).current!.isOpen, isFalse);
+  });
 }