Some fixes before finalization - #8

Process completed with exit code 1.

Unexpected input(s) 'gemini_api_key', valid inputs are ['github_token', 'api_key', 'provider', 'github_repository', 'pr_number', 'model', 'lean_keywords', 'style_guide_path', 'validate_title', 'upstream_path']

Can't add secret mask for empty string in ##[add-mask] command.