Alert history is organized by cycle, not by message — one heat event is one row, however many people it reached and however many times it was retried.
- The level it reached, and when.
- Everyone who was contacted, on which channel, and whether the provider confirmed delivery.
- Who acknowledged it and how long after the alert fired.
- Which escalation steps ran, if any did.
Readings themselves are never editable or deletable, here or anywhere else. A correction is recorded as a new flagged entry rather than a change to what was originally measured — a compliance record you can quietly rewrite is not a compliance record.