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/modules/voice/voice.service.ts

@@ -4,6 +4,7 @@ import {
   COMMAND_VOICE_CHANNELS,
   COMMAND_VOICE_CONNECT,
   COMMAND_VOICE_DISCONNECT,
+  CommandReply,
   VOICE_STATUS_KEY,
 } from "@bete/shared";
 import {
@@ -41,6 +42,18 @@ export const DEFAULT_VOICE_STATUS: VoiceStatus = {
   activeChannelName: null,
 };
 
+/**
+ * Wraps tryCommandThenFallback with a cleaner signature for use within this module.
+ * Attempts a Redis command first; on failure, falls back to the provided function.
+ */
+async function withFallback<T>(
+  commandFn: () => Promise<CommandReply<T> | null>,
+  fallbackFn: () => Promise<T>,
+  name: string,
+): Promise<T> {
+  return tryCommandThenFallback(commandFn, fallbackFn, name);
+}
+
 function readVoiceStatusFallback(): Promise<VoiceStatus> {
   return readRedisStatus(VOICE_STATUS_KEY).then(
     (cached) => (cached as unknown as VoiceStatus) ?? DEFAULT_VOICE_STATUS,
@@ -53,7 +66,7 @@ function readVoiceStatusFallback(): Promise<VoiceStatus> {
  */
 export async function getGuilds(): Promise<Guild[]> {
   logger.info("getGuilds called");
-  return tryCommandThenFallback(
+  return withFallback(
     () => publishCommand<Guild[]>(COMMAND_GUILDS_LIST, {}),
     async () => {
       const pool = getPool();
@@ -76,7 +89,7 @@ export async function getGuilds(): Promise<Guild[]> {
  */
 export async function getTextChannels(guildId: string): Promise<Channel[]> {
   logger.info({ guildId }, "getTextChannels called");
-  return tryCommandThenFallback(
+  return withFallback(
     () => publishCommand<Channel[]>(COMMAND_GUILDS_TEXT_CHANNELS, { guildId }),
     async () => {
       const pool = getPool();
@@ -122,7 +135,7 @@ export async function connectVoice(
   channelId: string,
 ): Promise<VoiceStatus> {
   logger.info({ guildId, channelId }, "connectVoice called");
-  return tryCommandThenFallback(
+  return withFallback(
     () =>
       publishCommand<VoiceStatus>(COMMAND_VOICE_CONNECT, {
         guildId,
@@ -138,7 +151,7 @@ export async function connectVoice(
  */
 export async function disconnectVoice(): Promise<VoiceStatus> {
   logger.info("disconnectVoice called");
-  return tryCommandThenFallback(
+  return withFallback(
     () => publishCommand<VoiceStatus>(COMMAND_VOICE_DISCONNECT, {}),
     () => readVoiceStatusFallback(),
     "disconnectVoice",