Legacy _resolve_and_check (Path|None, str tuple) now delegates to
_resolve_and_check_result (Result[Path]). The try/except Exception in the
legacy function is REMOVED; the new Result variant captures the structured
ErrorInfo (kind=INVALID_INPUT for path errors, kind=PERMISSION for
allowlist denials). Error messages are propagated via ui_message().
Updated tests/test_py_struct_tools.py::test_mcp_dispatch_errors to accept
the new 'permission' ErrorKind string instead of the legacy 'ACCESS DENIED'
substring (the new format is more descriptive).
Audit: mcp_client BC count 40 -> 39.
ed