The expression `str(path.stat().st_mtime_ns) if path.exists() else None`
has a TOCTOU race: the file can be deleted between exists() and stat().
The resulting FileNotFoundError propagates up to _watch_loop's except
handler, which records a breaker failure and terminates the loop — no
more push events are processed until restart.
Replace with a try/except around stat() and return early on
FileNotFoundError. The deletion event from watchfiles will handle
cleanup.
42922cd2bd