TTS-019: Update GenerateOptions/Result Types for TTS

[murdore]

Summary

Update the GenerateOptions and GenerateResult type definitions to include TTS configuration and results.

Technical Details

• File(s): src/lib/types/generateTypes.ts, src/lib/types/streamTypes.ts
• Effort: 1h

Acceptance Criteria

• [ ] Added tts?: TTSOptions field to GenerateOptions interface
• [ ] Added audio?: TTSResult field to GenerateResult interface
• [ ] Added audioChunk?: TTSChunk field to StreamChunk interface
• [ ] Updated JSDoc comments to explain TTS integration
• [ ] All existing tests pass after type changes
• [ ] TypeScript compilation passes

Dependencies

• Depends on: TTS-001
• Blocks: TTS-020, TTS-021

Priority: high | Effort: 1h | Complexity: simple