feat(tools): add base_url support to OpenAI TTS provider

Allow users to configure a custom base_url for the OpenAI TTS provider
in ~/.hermes/config.yaml under tts.openai.base_url. Defaults to the
official OpenAI endpoint. Enables use of self-hosted or OpenAI-compatible
TTS services (e.g. http://localhost:8000/v1).

Also adds a TTS configuration example block to cli-config.yaml.example.

tools/tts_tool.py

@@ -239,6 +239,7 @@ def _generate_openai_tts(text: str, output_path: str, tts_config: Dict[str, Any]
     oai_config = tts_config.get("openai", {})
     model = oai_config.get("model", DEFAULT_OPENAI_MODEL)
     voice = oai_config.get("voice", DEFAULT_OPENAI_VOICE)
+    base_url = oai_config.get("base_url", "https://api.openai.com/v1")
 
     # Determine response format from extension
     if output_path.endswith(".ogg"):
@@ -247,7 +248,7 @@ def _generate_openai_tts(text: str, output_path: str, tts_config: Dict[str, Any]
         response_format = "mp3"
 
     OpenAIClient = _import_openai_client()
-    client = OpenAIClient(api_key=api_key, base_url="https://api.openai.com/v1")
+    client = OpenAIClient(api_key=api_key, base_url=base_url)
     response = client.audio.speech.create(
         model=model,
         voice=voice,

website/docs/user-guide/features/voice-mode.md

@@ -404,6 +404,7 @@ tts:
   openai:
     model: "gpt-4o-mini-tts"
     voice: "alloy"                 # alloy, echo, fable, onyx, nova, shimmer
+    base_url: "https://api.openai.com/v1"  # optional: override for self-hosted or OpenAI-compatible endpoints
   neutts:
     ref_audio: ''
     ref_text: ''