feat: implement dynamic theme palette selection

- Introduced a new feature allowing users to select from multiple accent color palettes for buttons, cards, and chat bubbles.
- Added `AppThemePalette` provider to manage the current theme palette and persist user selections.
- Updated the `AppTheme` class to utilize the selected palette for light and dark themes, enhancing visual customization.
- Enhanced the `AppCustomizationPage` to include a palette selector, improving user experience and personalization options.
- Updated localization files to support new palette selection UI elements in multiple languages.

lib/features/chat/views/chat_page.dart

@@ -946,8 +946,7 @@ class _ChatPageState extends ConsumerState<ChatPage> {
     final greetingName = deriveUserDisplayName(user);
     return LayoutBuilder(
       builder: (context, constraints) {
-        return SingleChildScrollView(
-          physics: const AlwaysScrollableScrollPhysics(),
+        return Padding(
           padding: const EdgeInsets.all(Spacing.lg),
           child: ConstrainedBox(
             constraints: BoxConstraints(minHeight: constraints.maxHeight),