Configuration models with json/YAML instead of hardcode it like current approach

[JasonHonKL]

Is your feature request related to a problem? Please describe.

Current the code is fixed in the python script we write for example

    provider=ProviderConfig(
        default_provider="openai/gpt-4o",
        orchestrator_provider="anthropic/claude-sonnet-4-20250514",
        research_provider="openai/gpt-4o",
        engineer_provider="anthropic/claude-3-7-sonnet-20250219",
        ops_provider="anthropic/claude-3-7-sonnet-20250219",
        tool_provider="openai/gpt-4o",
    ),

however sometime we just want our user to use the library with json/yaml format instead of setting up like the code mentioned above

Describe the solution you'd like
I suggest to have a yaml config such that

providers:
 - default_provider: openai/gpt-4o
   orchestrator_provider: anthropic/claude-sonnet-4-20250514

 - default_provider: ... 

We could further set something like

python script.py --provider 2 

to select the provider

Describe alternatives you've considered
now it works but I mean with json and yaml it is more user friendly

Additional context
N/A