feat: Add PWA assets and metadata for iOS Safari installation

- Generate app icons in multiple sizes (192x192, 512x512, 180x180, 32x32)
- Create favicon and apple-touch-icon SVG files
- Add comprehensive PWA meta tags in app layout
- Configure theme color (#3B82F6) and background color
- Update manifest.json with icon references (PNG and SVG)
- Create icon generation scripts (SVG and PNG conversion)
- Add browser-based PNG icon generator (HTML)
- Create comprehensive PWA testing guide
- Add icon setup documentation

Requirements: 4.1, 4.2
Task: 13. Add PWA assets and metadata

.kiro/specs/ultimate-lists-app/tasks.md

@@ -176,7 +176,7 @@
   - **Property 13: Offline mutation synchronization**
   - **Validates: Requirements 4.5**
 
-- [ ] 13. Add PWA assets and metadata
+- [x] 13. Add PWA assets and metadata
   - Generate app icons in multiple sizes (192x192, 512x512)
   - Create favicon and apple-touch-icon
   - Add meta tags for PWA in app layout