Feature Request: Configure TTS voice, speaking rate, and pitch for VS Code Speech

[chengpochen]

Please add user-configurable text-to-speech controls for VS Code Speech in chat and voice interactions.

Problem
Currently, voice synthesis appears to use an internal/default voice path and does not provide a reliable per-user setting for:

• Voice selection (for example specific installed system voices)
• Speaking rate
• Pitch
• Changing system TTS voice in Windows does not affect VS Code Speech synthesis output

Suggestion
use the user's windows Narrator voice settings; there the user can install various voices and set the pitch, speed, and volume for the text to speech synthesis.