fix(ui): fix various UI issues (#1518)

ui/flutter/test/shared/widgets/app_path_placeholder_button_test.dart

@@ -0,0 +1,49 @@
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:shadcn_flutter/shadcn_flutter.dart' as shad;
+import 'package:gopeed/shared/theme/app_theme.dart';
+import 'package:gopeed/shared/widgets/app_path_placeholder_button.dart';
+
+void main() {
+  for (final width in [390.0, 1024.0]) {
+    testWidgets('path placeholders explain and insert variables at width $width', (tester) async {
+      tester.view.physicalSize = Size(width, 800);
+      tester.view.devicePixelRatio = 1;
+      addTearDown(tester.view.resetPhysicalSize);
+      addTearDown(tester.view.resetDevicePixelRatio);
+      final controller = TextEditingController(text: '/downloads/replace');
+      addTearDown(controller.dispose);
+      controller.selection = const TextSelection(baseOffset: 11, extentOffset: 18);
+      await tester.pumpWidget(
+        shad.ShadcnApp(
+          theme: AppTheme.light(),
+          materialTheme: AppTheme.materialLight(),
+          home: Center(child: AppPathPlaceholderButton(controller: controller)),
+        ),
+      );
+      await tester.tap(find.text('Insert Placeholder'));
+      await tester.pump();
+      await tester.pump(const Duration(milliseconds: 300));
+      expect(find.text('%year% — Current year'), findsOneWidget);
+      expect(find.text('%month% — Current month (01-12)'), findsOneWidget);
+      expect(find.text('%day% — Current day (01-31)'), findsOneWidget);
+      expect(find.text('%date% — Full date (YYYY-MM-DD)'), findsOneWidget);
+      expect(find.text('e.g. ${DateTime.now().year}'), findsOneWidget);
+      await tester.tap(find.byKey(const ValueKey('path-placeholder-%year%')));
+      await tester.pumpAndSettle();
+      expect(controller.text, '/downloads/%year%');
+      expect(controller.selection.baseOffset, controller.text.length);
+      expect(find.text('%year% — Current year'), findsNothing);
+      for (final variable in ['%month%', '%day%', '%date%']) {
+        controller.text = '/downloads/';
+        await tester.tap(find.text('Insert Placeholder'));
+        await tester.pump();
+        await tester.pump(const Duration(milliseconds: 300));
+        await tester.tap(find.byKey(ValueKey('path-placeholder-$variable')));
+        await tester.pumpAndSettle();
+        expect(controller.text, '/downloads/$variable');
+      }
+      expect(tester.takeException(), isNull);
+    });
+  }
+}