fix: preserve original name for warning in transform_string_function_style

[kuishou68]

Closes #2951

Problem

transform_string_function_style modified name (replacing spaces with _) before comparing it to transformed_name. This meant tool names containing only spaces (as invalid chars) never triggered the warning, even though the returned value silently differed from the original input.

Fix

Capture original_name = name before any mutation, and compare the final lowercased result against the original to decide whether to warn.

Signed-off-by: Cocoon-Break 54054995+kuishou68@users.noreply.github.com

[seratch]

Thanks for the report and the patch. The issue is valid: names with spaces are currently transformed before the warning comparison, so something like My Tool becomes my_tool without warning.

I’m going to handle the fix on our side rather than asking you to keep iterating on this PR. The main reason is that the safest change is a little narrower than the current patch: we should warn when the name needed character replacement, but we should not start warning for case-only normalization.

For example, this PR would also warn for:

MyTool -> mytool
transfer_to_Agent -> transfer_to_agent

Those names only contain letters, digits, and underscores, so the existing “invalid characters” warning would be misleading. It could also add warning noise for common agent and handoff names where uppercase letters are normal.

#2953 keeps the existing returned values, adds the missing warning for spaces/punctuation, and adds regression coverage for both replacement and case-only cases. I’ll close this PR once that lands. Thanks again for surfacing the bug.