.NET: Support programmatic parameter descriptions in AIFunctionFactory

Hello,

I have an issue regarding tool definitions.

AIFunctionFactory.Create cannot set parameter descriptions programmatically. It must use [Description] attributes in code, preventing external configuration.

Right now, parameter descriptions can only come from [Description] attributes in code:

public async Task<string> SearchAsync(
    [Description("The search query")]  // Must be in code
    string query
)

This means every time I want to tweak a parameter description to improve tool selection, I need to deploy new code. For comparison, I can already set the function name and description externally via AIFunctionFactoryOptions, but there's no equivalent for parameters.

Right now I'm stuck with a hybrid approach (function descriptions external, parameter descriptions in code), but it would be great to have consistency.

Let me know if you need any clarification or if there's a workaround I missed :)