Clog note: measure time to detect #6757

The clog-cleared note (#6524) leaves out "Time to detect" because the minute tick only learns of a clog when it declares it, so detection and start are the same moment. Store a real start (e.g. the first reading that crossed a threshold, or the oldest stuck item's age at declaration) in clog_state, pass it as startedAt to clogNote, and the line comes back on its own (it prints whenever detectedAt differs from startedAt).

Parked by the crew: the check stayed red through 2 automatic tries (pull #6769 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.

Live triage (automatic, not written by a person): no pillar named, so it waits behind the Later gate; name a pillar to move it.