The SW cache name was hardcoded to 'pinchchat-v1', meaning PWA users
would get stale cached assets forever. Now the cache name includes
the package version and build timestamp, so each build creates a new
cache and old ones are cleaned up on activation.
Also adds:
- Periodic SW update check (every 30 min)
- Auto-reload when new SW version is detected
- Add sw.js with stale-while-revalidate caching for static assets
- Network-first for HTML navigation, skip API/WS requests
- Register service worker in main.tsx on page load
- Enhanced manifest.json with orientation, categories, and all icon sizes
- App is now installable as a standalone PWA on mobile and desktop
- Add ThemeContext with CSS custom properties for all base colors
- Three theme modes: Dark (default), Light, OLED Black
- Six accent colors: Cyan, Violet, Emerald, Amber, Rose, Blue
- Theme switcher dropdown in header (palette icon)
- Persisted in localStorage
- CSS variables replace hardcoded hex colors in index.css and components
- i18n support (EN/FR) for theme labels
- Catches render errors and shows a styled recovery UI instead of blank white screen
- Try Again button re-renders, Reload button refreshes the page
- Error details shown in a collapsible pre block
- Full i18n support (EN/FR)
- Wraps the entire app in main.tsx
