A broken job state file is rejected once instead of warning over and over.
What's wrong with this entry?
The cache of per-job state files gained a mode where a failed read returns nothing rather than the last known state, and a state file that is oversized or not a regular file is rejected once instead of warning repeatedly.
- Modification-time keys, transient-error deduplication, prune reporting and sidecar-fallback logging moved from loose module-level maps into one object with named methods.
- Callers pick the behaviour by asking for the null-on-failure mode.
shouldReportTransient
Strings lifted out of the shipped bundle, so the claim above can be checked against them.