Major PWA and mobile UI improvements

- Fixed PWA installation on Android by correcting manifest.json icon configuration
- Made UI mobile-friendly with compact layout and sticky record button
- Implemented auto-translation after transcription stops
- Updated branding from 'Voice Translator' to 'Talk2Me' throughout
- Added reverse proxy support with ProxyFix middleware
- Created diagnostic tools for PWA troubleshooting
- Added proper HTTP headers for service worker and manifest
- Improved mobile CSS with responsive design
- Fixed JavaScript bundling with webpack configuration
- Updated service worker cache versioning
- Added comprehensive PWA documentation

These changes ensure the app works properly as a PWA on Android devices
and provides a better mobile user experience.

static/service-worker.js

@@ -1,10 +1,11 @@
 // Service Worker for Talk2Me PWA
 
-const CACHE_NAME = 'voice-translator-v1';
+const CACHE_NAME = 'talk2me-v4'; // Increment version to force update
 const ASSETS_TO_CACHE = [
   '/',
+  '/static/manifest.json',
   '/static/css/styles.css',
-  '/static/js/dist/app.js',
+  '/static/js/dist/app.bundle.js',
   '/static/icons/icon-192x192.png',
   '/static/icons/icon-512x512.png',
   '/static/icons/favicon.ico',