refactor: Migrate to Tweakcn themes and enhance UI consistency

- Replaced references to AppColorPalettes with TweakcnThemes across various files to standardize theme usage.
- Updated the AppTheme and AppColorTokens to utilize TweakcnThemeDefinition for improved theme management.
- Adjusted UI components in ChatPage, ChatsDrawer, AppCustomizationPage, and ProfilePage to align with the new theme structure, ensuring consistent styling and color application.
- Removed the deprecated color_palettes.dart file to streamline the theme architecture.

lib/core/services/enhanced_accessibility_service.dart

@@ -2,7 +2,7 @@ import 'dart:math' as math;
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter/semantics.dart';
-import '../../shared/theme/color_palettes.dart';
+import '../../shared/theme/tweakcn_themes.dart';
 import '../../shared/theme/theme_extensions.dart';
 
 /// Enhanced accessibility service for WCAG 2.2 AA compliance
@@ -349,7 +349,7 @@ class EnhancedAccessibilityService {
     return BoxDecoration(
       border: hasFocus
           ? Border.all(
-              color: focusColor ?? AppColorPalettes.auroraViolet.light.primary,
+              color: focusColor ?? TweakcnThemes.t3Chat.light.primary,
               width: borderWidth,
             )
           : null,