Adds a slim animated banner below the header that:
- Shows 'Connection lost — reconnecting…' with spinner when WS drops
- Flashes 'Reconnected!' with auto-dismiss after 3s on recovery
- Only appears after initial connection (not on first load)
- Supports EN/FR via i18n system
- Uses aria role=alert for accessibility
Floating button appears when user scrolls away from the bottom of the
conversation, making it easy to jump back to the latest messages.
Includes i18n labels (EN/FR) and smooth scroll animation.
- Lightweight i18n system in src/lib/i18n.ts (no external deps)
- All UI strings extracted to translation keys
- English (default) and French locales included
- Set VITE_LOCALE=fr in .env for French UI
- Fallback to English for unknown locales
- Add LoginScreen component with Gateway URL + Token fields
- Store credentials in localStorage (not in bundle)
- Auto-reconnect with stored credentials on reload
- Add logout button (LogOut icon) in Header
- Remove VITE_GATEWAY_TOKEN from .env.example
- VITE_GATEWAY_WS_URL now only pre-fills the URL field
- Dark neon theme consistent with rest of app
Closes feedback item #4
