feat(tts): add pitch and volume configuration options for Edge TTS

[ariel-ai-bot]

Summary

Add support for configurable pitch and volume adjustment in the Edge TTS provider. Previously, the _generate_edge_tts() function only read voice and speed from the config, ignoring pitch and volume entirely.

Changes

• tools/tts_tool.py:

  • Added DEFAULT_EDGE_PITCH = "+0Hz" and DEFAULT_EDGE_VOLUME = "+0%" constants
  • Modified _generate_edge_tts() to read pitch from tts.edge.pitch and volume from tts.edge.volume config
  • Passes both parameters to edge_tts.Communicate() when configured (defaults skip the parameters to maintain backward compatibility)

• website/docs/user-guide/configuration.md:

  • Added pitch: "+0Hz" and volume: "+0%" options under tts.edge: in the config example
  • Added pitch and volume format documentation explaining the formats (range: -100Hz~+100Hz for pitch, -100%~+100% for volume)

Config Usage

tts:
  provider: "edge"
  edge:
    voice: "zh-TW-HsiaoChenNeural"
    speed: 0.9
    pitch: "+50Hz"   # Higher pitch for cute/childlike voice
    volume: "+10%"   # Slightly louder

Verification

Confirmed that edge_tts.Communicate accepts pitch and volume parameters:

def __init__(
    self, text, voice, *, rate="+0%", volume="+0%", pitch="+0Hz",
    boundary="SentenceBoundary", connector=None, proxy=None,
    connect_timeout=10, receive_timeout=60
)

Source: https://github.com/rany2/edge-tts/blob/master/src/edge_tts/communicate.py

Type Safety

Added explicit type annotation kwargs: Dict[str, Any] for the kwargs dict to satisfy type checkers.

[alt-glitch]

Duplicate of #2965 which adds the same rate/pitch/volume controls for Edge TTS. Consider consolidating.

[ariel-ai-bot]

This PR is a duplicate of #2965, which already implements the same rate/pitch/volume controls for Edge TTS with additional validation, clamping, and test coverage. Closing this to avoid redundant changes.

Thank you @alt-glitch for the review and for pointing this out! 🙏