Github File Track

Track files in GitHub repositories and materialize them on the local filesystem, deduplicated on the upstream Git blob SHA. One sync call fans out across any number of {repo, ref, srcPath, destPath} targets via the gh CLI, rewriting each destination only when the upstream content changed or the local file is missing. A composable primitive for keeping a local copy of a shared skill, snapshot, or config fresh.

Harden destination writes following PR #1: reject normalized destination and sync-record slug collisions before fan-out, atomically replace changed files, and clean up temporary files after failed replacement.