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/redis-bridge.ts

@@ -15,7 +15,7 @@ import {
 import { createChildLogger } from "@bete/shared/logger";
 import Redis from "ioredis";
 import { config } from "../shared/config/index.js";
-import { broadcastRaw } from "./broadcast.js";
+import { broadcastEvent } from "./broadcast.js";
 
 const logger = createChildLogger("ws.redis-bridge");
 
@@ -77,7 +77,7 @@ function handleSubscriptionMessage(channel: string, message: string): void {
     { channel, eventType: mapping.eventType },
     "Broadcasting Redis event",
   );
-  broadcastRaw(mapping.eventType, data);
+  broadcastEvent(mapping.eventType, data);
 }
 
 export async function startRedisBridge(): Promise<void> {