Add settings as canonical init arg for all AIService descendants, deprecate redundant model/voice/params args

ServiceSettings types were introduced for runtime updates via ServiceUpdateSettingsFrame, but there was tension between init-time and runtime APIs: overlapping-but-different InputParams vs ServiceSettings classes, and runtime-updatable fields like `model` and `voice` scattered as direct init args rather than living in a settings object. This unifies them so developers use the same settings type at both init and runtime, improving ergonomics and consistency.

Every concrete AIService subclass (LLM, TTS, STT, ImageGen, Vision, Video) now accepts a `settings` parameter for runtime-updatable config. Old init args (`model`, `voice_id`, `params`/`InputParams`) still work but emit DeprecationWarnings pointing to the new API. When both are provided, `settings` takes precedence. Leaf classes emit warnings; base classes do not, avoiding double warnings in inheritance chains.

src/pipecat/services/cerebras/llm.py

@@ -6,10 +6,14 @@
 
 """Cerebras LLM service implementation using OpenAI-compatible interface."""
 
+from typing import Optional
+
 from loguru import logger
 
 from pipecat.adapters.services.open_ai_adapter import OpenAILLMInvocationParams
+from pipecat.services.openai.base_llm import OpenAILLMSettings
 from pipecat.services.openai.llm import OpenAILLMService
+from pipecat.services.settings import _warn_deprecated_param
 
 
 class CerebrasLLMService(OpenAILLMService):
@@ -24,7 +28,8 @@ class CerebrasLLMService(OpenAILLMService):
         *,
         api_key: str,
         base_url: str = "https://api.cerebras.ai/v1",
-        model: str = "gpt-oss-120b",
+        model: Optional[str] = None,
+        settings: Optional[OpenAILLMSettings] = None,
         **kwargs,
     ):
         """Initialize the Cerebras LLM service.
@@ -33,9 +38,22 @@ class CerebrasLLMService(OpenAILLMService):
             api_key: The API key for accessing Cerebras's API.
             base_url: The base URL for Cerebras API. Defaults to "https://api.cerebras.ai/v1".
             model: The model identifier to use. Defaults to "gpt-oss-120b".
+
+                .. deprecated:: 1.0
+                    Use ``settings=OpenAILLMSettings(model=...)`` instead.
+
+            settings: Runtime-updatable settings. When provided alongside deprecated
+                parameters, ``settings`` values take precedence.
             **kwargs: Additional keyword arguments passed to OpenAILLMService.
         """
-        super().__init__(api_key=api_key, base_url=base_url, model=model, **kwargs)
+        if model is not None:
+            _warn_deprecated_param("model", "OpenAILLMSettings", "model")
+
+        default_settings = OpenAILLMSettings(model=model or "gpt-oss-120b")
+        if settings is not None:
+            default_settings.apply_update(settings)
+
+        super().__init__(api_key=api_key, base_url=base_url, settings=default_settings, **kwargs)
 
     def create_client(self, api_key=None, base_url=None, **kwargs):
         """Create OpenAI-compatible client for Cerebras API endpoint.