fix: make header names python-safe

[saurabhkoshatwar]

Fixes #580

Summary

• Allow Toolbox tools to use parameter/header names that are not valid Python identifiers (e.g. X-Application-ID).
• Introduce a Python‑safe field name mapping so function signatures and Pydantic models stay valid while preserving the original parameter names over the wire.

Details

• Sanitize schema parameter names into Python‑safe field names and use those in inspect.Parameter and Pydantic models.
• Maintain a mapping from Python‑safe names back to original schema names in ToolboxTool so requests still use the exact header/parameter names defined in tools.yaml.

[anubhav756]

/gcbrun

[anubhav756]

Thanks for the PR @saurabhkoshatwar !

Could you please take a look at the integration test failure?

I'm also thinking if we could add any more integration/unit tests to verify this change. For instance to see if there could still be any validation failures while actually using hyphenated parameters?