Resolve the most recent modification time for a file. Prefers the git commit timestamp (deterministic across machines / CI runners); falls back to filesystem mtime, then to the current ISO timestamp as a last resort. Always returns an ISO-8601 string.
Resolve the most recent modification time for a file. Prefers the git commit timestamp (deterministic across machines / CI runners); falls back to filesystem mtime, then to the current ISO timestamp as a last resort. Always returns an ISO-8601 string.