Module Utils/Fs/AtomicWrite

Idempotent and atomic file write primitives.

writeFileIfChanged / writeFileContent preserve mtime when the on-disk bytes already match (idempotency contract for aws s3 sync).
atomicWrite writes via a unique temp file + rename with retries, tolerating concurrent writers on Windows-like filesystems.
resolveUniqueFilePath produces non-clobbering numeric suffixes.

Functions