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).

frontend/src/components/Scheduler.tsx

@@ -35,7 +35,7 @@ import { useContextMenu } from "./ui/useContextMenu";
 import { ContextMenu } from "./ui/ContextMenu";
 import { MoreButton } from "./ui/MoreButton";
 import { type ActionMenuItem } from "./ui/ActionMenu";
-import { jobResultText } from "../lib/jobResult";
+import { jobFailureText, jobResultText } from "../lib/jobResult";
 
 const POLL_MS = 4000;
 // While any job is running, poll faster so short scheduled runs aren't missed between ticks.
@@ -257,7 +257,10 @@ function JobRow({
               ? t("scheduler.lastRun", { time: relativeTime(job.last_finished, lang) })
               : t("scheduler.neverRun")}
           {job.last_error ? (
-            <span className="text-danger"> · {job.last_error}</span>
+            <span className="text-danger">
+              {" · "}
+              {jobFailureText(t, job.result, lang) ?? job.last_error}
+            </span>
           ) : job.result ? (
             <span> · {jobResultText(t, job.result, lang)}</span>
           ) : job.last_result ? (