Prevent arbitrary file write and repo traversal by strictly validating
`github_repo` and `file_path` inputs in `update_github_cdn_urls`.
Added `validate_github_repo` and `validate_file_path` functions to
enforce strict whitelisting of characters and reject path traversal sequences.
Added comprehensive unit tests in `tests/test_github_validation.py`.
google-labs-jules[bot]
e1f9b50c3d