Add support for image input in model resources and enhance related configurations

- Introduce a new `support_image_input` field in model resources, allowing models to indicate support for image input.
- Update the backend models, schemas, and database seed scripts to accommodate the new field.
- Enhance the AssistantConfig and related routes to handle image input capabilities, ensuring proper validation and error handling.
- Modify the frontend components to include toggles for enabling visual understanding and filtering models based on image input support.
- Implement necessary adjustments in the voice preview and pipeline to integrate video stream handling alongside audio functionalities.

backend/models.py

@@ -41,6 +41,7 @@ class AssistantConfig(BaseModel):
     tts_interface_type: str = "openai-tts"
     llm_values: dict = {}
     llm_secrets: dict = {}
+    llm_support_image_input: bool = False
     stt_values: dict = {}
     stt_secrets: dict = {}
     tts_values: dict = {}
@@ -80,3 +81,4 @@ class SignalingOffer(BaseModel):
     type: str
     assistant_id: str | None = None
     inline_config: AssistantConfig | None = None
+    vision_enabled: bool = False