fix(scheduler,i18n): a failure a job names reads in the reader's language

The audit log showed a failed RSS poll as the server's English sentence
under a Hungarian UI. A job can now raise progress.JobFailed(reason,
message, **params): the scheduler stores the reason and params as the
run's data (dashboard, manual-run notice, audit row) beside the English
line, and the client renders scheduler.failure.<reason>. The RSS outage
names its first channel and the reason code (HTTP 404 vs unreachable).
An upstream's own error text stays as raised (diagnostic).

backend/app/scheduler.py

@@ -231,17 +231,22 @@ def _job(name: str, fn) -> None:
         db.rollback()
         log.exception("job %s failed", name, extra=logs.event("scheduler.job.failed", job=name))
         err = str(exc) or exc.__class__.__name__
+        # A failure the job named (progress.JobFailed) rides along as data, as a result does, so the
+        # client says it in the reader's language; `err` stays the English line.
+        failure = (
+            {"failure": exc.reason, **exc.params} if isinstance(exc, progress.JobFailed) else None
+        )
         _record(
             name,
             status="error",
             last_finished=_now_iso(),
             last_error=err,
-            result=None,
+            result=failure,
             progress=None,
         )
         if actor_id is not None:
-            _notify_done(db, actor_id, name, "error", err)
-        _audit_run(db, actor_id, name, "error", err, None)
+            _notify_done(db, actor_id, name, "error", err, failure)
+        _audit_run(db, actor_id, name, "error", err, failure)
     finally:
         # ALWAYS release the claim, even if the body raised before its own status update — so a
         # failure can never wedge the job as permanently "running".