✨ feat(ui): add settings menu and mask opacity control

- Add SettingsMenu component for quick navigation between settings sections
- Add mask opacity control to adjust overlay transparency
- Optimize search suggestions with immediate response and smooth animations
- Refine component styles for more compact interface
- Fix Translation interface type definition for maskOpacity
- Unify Bilibili API path to simplify environment handling

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/types.ts

@@ -30,6 +30,7 @@ export interface UserSettings {
   themeColor: string;
   searchOpacity: number;
   enableMaskBlur: boolean;
+  maskOpacity: number;
   backgroundUrl: string;
   backgroundType: BackgroundType;
   wallpaperFit: WallpaperFit;
@@ -38,3 +39,5 @@ export interface UserSettings {
   searchHistory: string[];
   language: Language;
 }
+
+export type SettingsSection = 'general' | 'wallpaper' | 'search';