feat: implement WebCodecs Opus decode for browser listen

- Add broadcastOpusToWeb to PcmBroadcaster interface for raw Opus packets
- Server broadcasts Opus frames with mode byte (1) + user hash + packet data
- Browser detects packet mode: mode=1 for Opus, mode=0 for legacy PCM
- Implement WebCodecs AudioDecoder for Opus decoding in browser
- Keep existing PCM playback as fallback for compatibility
- Show error if WebCodecs unsupported
- Fixes listen feature under Bun where native Opus decode unavailable

package.json

@@ -30,6 +30,8 @@
     "pino-http": "^11.0.0",
     "prism-media": "2.0.0-alpha.0",
     "prom-client": "^15.1.3",
+    "react": "^19.2.6",
+    "react-dom": "^19.2.6",
     "sodium-native": "^4.3.2",
     "ws": "^8.20.1",
     "zod": "^4.4.3"
@@ -39,6 +41,8 @@
     "@types/better-sqlite3": "^7.6.13",
     "@types/express": "^5.0.6",
     "@types/fluent-ffmpeg": "^2.1.28",
+    "@types/react": "^19.2.14",
+    "@types/react-dom": "^19.2.3",
     "@types/ws": "^8.18.1",
     "bun-types": "latest",
     "pino-pretty": "^10.3.1",