Feature Request: Add Chatterbox TTS Support

Description

Add Chatterbox (local TTS) as a native TTS provider option in OpenClaw.

Why Chatterbox?

• Local TTS (no API costs)
• High quality voice generation
• Custom voice cloning from audio samples
• Privacy-friendly (runs locally)

Use Case

Users want to use their own custom voice instead of cloud TTS providers.

Suggested Implementation

Add chatterbox to TTS provider options:

"tts": {
  "provider": "chatterbox",
  "chatterbox": {
    "voiceRef": "/path/to/reference.wav"
  }
}

Environment

• OpenClaw: 2026.3.13
• Platform: macOS