fix(#388): address PR review findings — fix WebSocket/REST bugs, improve error handling, fix types and comments

Critical fixes:
- Fix FormData field name mismatch (audio -> file) to match backend FileInterceptor
- Add /speech namespace to WebSocket connection URL
- Pass auth token in WebSocket handshake options
- Wrap audio.play() in try-catch for NotAllowedError and DOMException handling
- Replace bare catch block with named error parameter and descriptive message
- Add connect_error and disconnect event handlers to WebSocket
- Update JSDoc to accurately describe batch transcription (not real-time partial)

Important fixes:
- Emit transcription-error before disconnect in gateway auth failures
- Capture MediaRecorder error details and clean up media tracks on error
- Change TtsDefaultConfig.format type from string to AudioFormat
- Define canonical SPEECH_TIERS and AUDIO_FORMATS arrays as single source of truth
- Fix voice count from 54 to 53 in provider, AGENTS.md, and docs
- Fix inaccurate comments (Piper formats, tier prop, SpeachesProvider, TextValidationPipe)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/api/src/speech/providers/tts-provider.factory.ts

@@ -18,7 +18,7 @@ import { ChatterboxTTSProvider } from "./chatterbox-tts.provider";
 import { KokoroTtsProvider } from "./kokoro-tts.provider";
 import { PiperTtsProvider } from "./piper-tts.provider";
 import type { ITTSProvider } from "../interfaces/tts-provider.interface";
-import type { SpeechTier, AudioFormat } from "../interfaces/speech-types";
+import type { SpeechTier } from "../interfaces/speech-types";
 import type { SpeechConfig } from "../speech.config";
 
 // ==========================================
@@ -44,7 +44,7 @@ export function createTTSProviders(config: SpeechConfig): Map<SpeechTier, ITTSPr
     const provider = new KokoroTtsProvider(
       config.tts.default.url,
       config.tts.default.voice,
-      config.tts.default.format as AudioFormat
+      config.tts.default.format
     );
     providers.set("default", provider);
     logger.log(`Registered default TTS provider: kokoro at ${config.tts.default.url}`);