Previously ValidateParams ran before WORK_DIR injection and file_ids mapping,
causing required parameter missing errors for auto-handled params. Now the
execution order is: inject WORK_DIR, map file_ids to file params, validate, resolve.
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>