fix(voice): restore voice features and apply critical optimizations

Voice Feature Restoration:
- Implemented full Redis pub/sub pipeline for real-time voice data
- Added VOICE_PCM and VOICE_ACTIVE_USER Redis channels
- Implemented EventBroadcaster.voicePcmData() and voiceActiveUser() methods
- Extended backend redis-bridge to subscribe to voice channels
- Updated backend WebSocket server for binary PCM broadcast
- Replaced globalThis PcmBroadcaster pattern with proper EventBroadcaster DI
- Fixed root cause: PcmBroadcaster functions were never initialized

Bug Fixes:
- Fixed prism-media version conflict (2.0.0-alpha.0 → 1.3.5)
- Fixed type inconsistency in commandHandler.ts (AudioPlayerStatus → string)

Critical Optimizations:
- P1.1: Fixed unbounded memory growth in aiAnalyzer (added LRU caching, max 10K entries)
- P1.2: Converted sync file I/O to async in audio hot paths (recorder, sessionRecording)
- P1.3: Replaced process.exit(1) with proper error handling (bootstrap, aiAnalysisWorker)

Code Quality:
- Removed unused logger field in EventBroadcaster
- Replaced console.* with structured logger.* calls (player, decoder)
- Fixed typos and removed commented debug code
- Added DatabaseError class for better error handling

Files Modified: 18 (discord-gateway: 14, backend: 3, root: 1)
Architecture: Discord → EventBroadcaster → Redis → Backend WebSocket → Frontend

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

services/backend/src/ws/server.ts

@@ -1,6 +1,6 @@
 import type { Server } from "node:http";
-import { WebSocket, WebSocketServer } from "ws";
 import { createChildLogger } from "@bete/shared/logger";
+import { WebSocket, WebSocketServer } from "ws";
 
 const logger = createChildLogger("ws.server");
 
@@ -10,18 +10,6 @@ interface BroadcastEvent {
   timestamp: string;
 }
 
-declare global {
-  var __broadcastFns:
-    | {
-        messageCreated: (data: unknown) => void;
-        messageUpdated: (data: unknown) => void;
-        messageDeleted: (data: unknown) => void;
-        attachmentUploaded: (data: unknown) => void;
-        raw: (type: string, data: unknown) => void;
-      }
-    | undefined;
-}
-
 async function sendInitialStates(ws: WebSocket): Promise<void> {
   // Send initial user state
   ws.send(
@@ -128,6 +116,18 @@ export function createWebSocketServer(server: Server): WebSocketServer {
     }
   }
 
+  function broadcastRaw(data: Buffer) {
+    for (const client of clients) {
+      if (client.readyState === WebSocket.OPEN) {
+        try {
+          client.send(data);
+        } catch (err) {
+          logger.error({ err }, "Failed to broadcast binary data to client");
+        }
+      }
+    }
+  }
+
   globalThis.__broadcastFns = {
     messageCreated: (data: unknown) =>
       broadcast({ type: "message_created", data }),
@@ -138,6 +138,7 @@ export function createWebSocketServer(server: Server): WebSocketServer {
     attachmentUploaded: (data: unknown) =>
       broadcast({ type: "attachment_uploaded", data }),
     raw: (type: string, data: unknown) => broadcast({ type, data }),
+    binary: broadcastRaw,
   };
 
   // Cleanup on close