refactor(voice): optimize recording pipeline and improve performance

Refactor the voice recording and playback systems to improve efficiency, reduce latency, and enhance Docker build performance.

- **Infrastructure**: Optimize Dockerfiles using build mounts for pnpm cache and reorder layers for better caching of dependencies and build tools.
- **Backend/Gateway**:
  - Refactor `broadcast` module to use a generic event-based system instead of hardcoded functions.
  - Simplify voice recording logic by merging metadata and segment management into a unified `segment.ts`.
  - Optimize audio downsampling in `streamSetup.ts` using `Int16Array` views for better performance.
  - Implement `withFallback` utility for more robust Redis/Database command execution.
- **Frontend**:
  - Optimize audio playback visualization using pre-computed level shapes and efficient RMS calculation.
  - Reduce latency in voice commands by prioritizing WebSocket communication over HTTP.
  - Improve base64 encoding efficiency in audio transmission.
- **General**:
  - Add default value for `ADMIN_PASSWORD` in shared config.
  - Fix Docker healthcheck to use `127.0.0.1` instead of `localhost`.

services/backend/src/ws/server.ts

@@ -191,34 +191,10 @@ export function createWebSocketServer(server: Server): WebSocketServer {
     }
   }
 
-  setBroadcastFunctions({
-    messageCreated: (data: unknown) =>
-      broadcast({ type: "message_created", data }),
-    messageUpdated: (data: unknown) =>
-      broadcast({ type: "message_updated", data }),
-    messageDeleted: (data: unknown) =>
-      broadcast({ type: "message_deleted", data }),
-    messageAnalyzed: (data: unknown) =>
-      broadcast({ type: "message_analyzed", data }),
-    attachmentCreated: (data: unknown) =>
-      broadcast({ type: "attachment_created", data }),
-    attachmentUploaded: (data: unknown) =>
-      broadcast({ type: "attachment_uploaded", data }),
-    voiceRecordingStarted: (data: unknown) =>
-      broadcast({ type: "voice_recording_started", data }),
-    voiceRecordingStopped: (data: unknown) =>
-      broadcast({ type: "voice_recording_stopped", data }),
-    voiceRecordingUploaded: (data: unknown) =>
-      broadcast({ type: "voice_recording_uploaded", data }),
-    voicePcmData: (data: unknown) =>
-      broadcast({ type: "voice_pcm_data", data }),
-    voiceActiveUser: (data: unknown) =>
-      broadcast({ type: "voice_active_user", data }),
-    analysisQueueStatus: (data: unknown) =>
-      broadcast({ type: "analysis_queue_status", data }),
-    raw: (type: string, data: unknown) => broadcast({ type, data }),
-    binary: broadcastBinary,
-  });
+  setBroadcastFunctions(
+    (type: string, data: unknown) => broadcast({ type, data }),
+    broadcastBinary,
+  );
 
   // Cleanup on close
   wss.on("close", () => {