Memo: Loop Watch (Read Only When Polling Inside a Session)

Fixed schedule: one background shell loop with unique sentinel + regex, smoke-check once, run prompt immediately, tick acts on latest payload only. Dynamic: run now, arm event watcher if any, plus one-shot long heartbeat as fallback; re-arm after each wake. Unique sentinel per loop; no duplicate loops; on stop kill PIDs and consume the completion tick. Title commands as Loop <schedule>: <prompt>.