TTS-021: Integrate TTS into BaseProvider.stream()

[murdore]

Summary

Integrate streaming TTS synthesis into the BaseProvider.stream() method.

Technical Details

• File(s): src/lib/core/baseProvider.ts
• Effort: 4h

Acceptance Criteria

• [ ] Check if options.tts?.enabled === true in stream() method
• [ ] Create async generator that yields both text and audio chunks
• [ ] Extract text from each StreamChunk
• [ ] Buffer text chunks and call TTSProcessor.synthesizeStream()
• [ ] Yield original StreamChunk (text) followed by audioChunk
• [ ] Handle errors gracefully
• [ ] Add TTS latency to chunk metadata
• [ ] Document behavior in JSDoc comments
• [ ] Integration test: stream() with TTS returns audio chunks

Dependencies

• Depends on: TTS-001, TTS-004, TTS-009, TTS-013, TTS-017, TTS-019
• Blocks: none

Priority: high | Effort: 4h | Complexity: complex