feat: add model field patch

[sigoden]

Now, model definition can have its own patch configuration.

...
    - name: o3-mini-high
      real_name: o3-mini
      max_input_tokens: 200000
      input_price: 1.1
      output_price: 4.4
      supports_vision: true
      supports_function_calling: true
      supports_reasoning: true
      no_temperature: true
      system_prompt_prefix: Formatting re-enabled
      patch:
        body:
          reasoning_effort: high

...
    - name: gemini-2.0-flash-online
      real_name: gemini-2.0-flash
      max_input_tokens: 1048576
      max_output_tokens: 8192
      supports_vision: true
      supports_function_calling: true
      patch:
        body:
          tools: 
            - google_search: {}