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/discord-gateway/src/modules/event-broadcaster/eventBroadcaster.ts

@@ -43,11 +43,9 @@ export class RedisEventPublisher {
 
 export class EventBroadcaster {
   private publisher: RedisEventPublisher;
-  private logger: CustomLogger;
 
-  constructor(publisher: RedisEventPublisher, logger: CustomLogger) {
+  constructor(publisher: RedisEventPublisher) {
     this.publisher = publisher;
-    this.logger = logger;
   }
 
   async messageCreated(data: unknown): Promise<void> {
@@ -131,6 +129,49 @@ export class EventBroadcaster {
     });
   }
 
+  /**
+   * Broadcasts PCM audio data for real-time voice streaming
+   * @param pcmBuffer - Raw PCM audio buffer
+   * @param userId - Discord user ID
+   * @param metadata - Optional metadata about the audio chunk
+   */
+  async voicePcmData(
+    pcmBuffer: Buffer,
+    userId: string,
+    metadata?: any,
+  ): Promise<void> {
+    await this.publisher.publish("discord:voice:pcm", {
+      type: "voice_pcm_data",
+      data: {
+        userId,
+        pcm: pcmBuffer.toString("base64"),
+        metadata,
+      },
+      timestamp: Date.now(),
+      source: "discord-gateway",
+    });
+  }
+
+  /**
+   * Broadcasts voice user activity state changes
+   * @param userId - Discord user ID
+   * @param data - User state data including username, avatar, and speaking status
+   */
+  async voiceActiveUser(
+    userId: string,
+    data: { username: string; avatar: string; speaking: boolean },
+  ): Promise<void> {
+    await this.publisher.publish("discord:voice:active_user", {
+      type: "voice_active_user",
+      data: {
+        userId,
+        ...data,
+      },
+      timestamp: Date.now(),
+      source: "discord-gateway",
+    });
+  }
+
   async analysisQueueStatus(data: unknown): Promise<void> {
     await this.publisher.publish("discord:analysis:queue_status", {
       type: "analysis_queue_status",

services/discord-gateway/src/modules/event-broadcaster/eventTypes.ts

@@ -15,6 +15,9 @@ export const EventChannels = {
   VOICE_STARTED: "discord:voice:started",
   VOICE_STOPPED: "discord:voice:stopped",
   VOICE_UPLOADED: "discord:voice:uploaded",
+  // Real-time voice streaming channels
+  VOICE_ACTIVE_USER: "discord:voice:active_user", // Active speaker state updates
+  VOICE_PCM: "discord:voice:pcm", // Live PCM audio data stream
   ANALYSIS_QUEUE_STATUS: "discord:analysis:queue_status",
 } as const;