Update frontend branding from 'Voice Language Translator' to 'Talk2Me'

- Updated page title in index.html
- Updated main heading in index.html
- Updated PWA manifest name
- Updated service worker comment

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

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

static/service-worker.js

@@ -1,4 +1,4 @@
-// Service Worker for Voice Language Translator PWA
+// Service Worker for Talk2Me PWA
 
 const CACHE_NAME = 'voice-translator-v1';
 const ASSETS_TO_CACHE = [