fix(scheduler): show progress for any running job with reliable live updates

The dashboard now renders a progress bar for any running job — determinate
when counts are reported, an indeterminate "working" sliver otherwise — so a
scheduled run is as visible as a manual one (progress was never manual-only;
the wiring is shared, but only some jobs reported and the display gated on
counts).

Poll faster (1.5s) while any job runs, easing back to 4s when idle, derived
from the freshest data by react-query's functional refetchInterval. The
earlier React-state approach to this stalled the live updates (the row froze
on the first sampled value); useLiveQuery now accepts a function of the data.
Trilingual phase labels for the newly-reporting jobs.

frontend/src/i18n/locales/de/scheduler.json

@@ -38,7 +38,12 @@
     "enrich": "Videos anreichern",
     "backfill_recent": "Neue Uploads nachladen",
     "backfill_deep": "Ganze Historie nachladen",
-    "probe": "Shorts klassifizieren"
+    "probe": "Shorts klassifizieren",
+    "rss_poll": "Auf neue Uploads prüfen",
+    "subscriptions": "Abos synchronisieren",
+    "autotag": "Kanäle automatisch taggen",
+    "playlist_sync": "Playlists synchronisieren",
+    "working": "Arbeitet…"
   },
   "maintenance": {
     "title": "Wartung",