Update tests and implementation to use the new ordered map-based
ToolCallFunctionArguments type which replaces the previous map[string]any.
- Add mapToArgs helper to convert map[string]any to ToolCallFunctionArguments
- Add testArgs and testProps helpers in tests
- Use cmpopts.IgnoreUnexported for cmp.Diff comparisons
Use w.ResponseWriter.Status() instead of parsing StatusCode from JSON
payload. routes.go typically sends errors as gin.H{"error": "..."}
without a StatusCode field, causing all errors to be mapped to
"api_error" instead of the appropriate type (not_found_error,
invalid_request_error, etc.).
Added tests to verify error handling for common routes.go patterns.
ParthSareen