- A derived monitor outage with no `resolved_at` went to `History`, so an
ongoing disruption was listed under "Past incidents" while the component pill
beside it read Down. Unresolved now goes to `ActiveIncidents`.
- `overallState` returned `up` when nothing was counted: "all systems
operational" claimed from no evidence at all. A page with no components now
reports `no_data`, which the view already renders as "Status unknown".
- `EnsureStatusPageIndexes` returned on the first failure, so a transient
failure on the `status_pages` index left `status_incidents` with no unique
`(instance_id, incident_id)` index — a correctness property, not a scan
optimisation. All three are attempted and the failures joined.