Review follow-ups on the degraded-observation fix:

- processPace now mirrors the quota carry: an unreadable percentage is
  not a recovered pace condition, so an active pace baseline survives a
  degraded pass instead of re-announcing on recovery.
- prime mode no longer primes a scope from an error observation with
  zero usage rows; the scope stays unprimed so the first healthy pass
  establishes thresholds silently while the status record keeps the
  incident state.
- the errored-pass test now pins pace and reset preservation and the
  post-outage reset firing; new tests cover the pace carry and the
  errored first prime pass.

Red/green: 439 pass / 0 fail with the fixes; on the parent module
exactly the six degraded-observation tests fail (433 pass / 6 fail).