0e74a16b40
- Backend: added transcribe_audio (gpt-4o-transcribe), switched audio handler to full blob -> REST -> LLM -> streaming TTS - Frontend: MediaRecorder (webm/opus) full recording sent on stop (one blob per utterance) - Removed dead WhisperStream callbacks and pending_transcript/lock - This unblocks voice per AUDIT item 1 (Option B fallback). Deltas will come in later item. - Also preps for deprecation fix (MediaRecorder is the good path).