feat(call): migrate from WebRTC to LiveKit

Replace the custom WebRTC implementation with LiveKit for improved
stability and feature support.

- Remove `react-native-webrtc` and custom `WebRTCManager`
- Implement `LiveKitService` for room and track management
- Update `callStore` to handle LiveKit events and connection states
- Refactor `CallScreen` (mobile and web) to use `@livekit/react-native`
  and `VideoView`
- Update WebSocket protocol to use `call_ready` instead of manual SDP/ICE
  exchanges
- Add necessary camera and microphone permissions to `app.json`
- Update Metro and Babel configurations for LiveKit compatibility

package.json

@@ -63,7 +63,9 @@
     "react-native-share": "^12.2.6",
     "react-native-sse": "^1.2.1",
     "react-native-web": "^0.21.0",
-    "react-native-webrtc": "^124.0.7",
+    "@livekit/react-native": "^2.11.0",
+    "@livekit/react-native-webrtc": "^144.1.0",
+    "livekit-client": "^2.19.0",
     "react-native-webview": "13.16.0",
     "react-native-worklets": "0.7.2",
     "zod": "^4.3.6",