Backend stamps last_fire_error ({at, detail}) on a job when a scheduled fire
can't reach the gateway loopback (gateway down / api_server not bound) —
the "job runs manually but never auto-fires" case. Previously invisible in
mobile.
- CronJob.kt: model as CronJobFireError(at, detail) — the backend sends a
nested object, NOT a flat string (issue's String? proposal would fail to
deserialize), plus the last_fire_error field.
- CronJobsScreen: "Fire failed" ERROR badge in the list + "Dispatch Error"
row (detail + timestamp) in the Run Details dialog.
- Strings en/zh/ko. Test: job with last_fire_error loads + parses.
Backward-compatible: field has a default, existing jobs without it parse fine.
Co-authored-by: M57 <hy4ri@users.noreply.github.com>
