Replace hardcoded English strings in 32 Dart source files with l10n
references. Covers settings labels, UI actions, map/SAR features,
device config, notifications, profiles, spectrum scan, and status
messages for sl, de, hr, pl, es, fr, it, el, ru, tr, uk, zh, pt.
- Remove SseClientService and ConnectionMode.sseClient
- Add ConnectionMode.tcp with MeshCoreTcpService (port 5000)
- NetworkScannerService: scan TCP port 5000 via raw Socket.connect
- mDNS service type changed to _meshcore._tcp
- connection_dialog: connect via connectTcp() instead of connectToSseServer()
- home_screen: show WiFi icon and label for TCP mode
- Bump meshcore_client to pick up TCP transport support
