feat(scheduler): each row shows its last three runs, an interrupted run as such, and the ad-hoc runs beside the jobs

A row's one dot said how the LAST run went, and an interrupted run fell through to "idle" — a grey dot
that read as "no run recorded". The row now leads with its last three runs, newest first, each named
for a screen reader and in its tooltip (how it went, when, who started it); an interrupted run is a
ring, set apart from a skipped run and a failure, and its line says the server restarted under it.

A channel's full-history backfill gets its own "Ad-hoc runs" block: its runs, its channel and what
it fetched, no interval and no run button — it needs its target. AD_HOC_JOBS names every such job;
the backend-id contract holds their names in both languages, and run_ad_hoc refuses any other id.

backend/tests/test_scheduler.py

@@ -13,7 +13,7 @@ import pytest
 from sqlalchemy import select
 
 from app import jobruns, logs, logsink, quota, scheduler, state
-from app.models import AuditLog, JobRun, Notification, QuotaEvent
+from app.models import AuditLog, Channel, JobRun, Notification, QuotaEvent
 from app.runstatus import RunStatus, RunTrigger
 
 _JOB = "unit_test_claim"  # not a real job id — exercises the primitive without touching live jobs
@@ -335,10 +335,43 @@ def test_an_ad_hoc_run_is_the_users_run_of_its_target_with_its_spend_and_failure
     assert (failed.status, failed.error) == ("error", "quota exceeded")
 
 
+def test_the_page_shows_the_ad_hoc_runs_beside_the_jobs_with_their_channel(db, make_user):
+    user = make_user("shown@example.com")
+    db.add(Channel(id="UC_shown", title="BBC Earth"))
+    db.commit()
+    scheduler._ad_hoc("channel_backfill", lambda: {"skipped": "at capacity"}, user.id, "UC_none")
+    scheduler._ad_hoc("channel_backfill", lambda: {"videos_added": 69}, user.id, "UC_shown")
+
+    (row,) = scheduler.scheduler_snapshot(db)["ad_hoc"]
+    assert (row["id"], row["running"], row["target"], row["target_title"]) == (
+        "channel_backfill",
+        False,
+        "UC_shown",
+        "BBC Earth",
+    )
+    assert (row["status"], row["result"], row["last_trigger"]) == (
+        "ok",
+        {"videos_added": 69},
+        "ad_hoc",
+    )
+    assert len(row["recent"]) == 2
+    assert all(j["id"] != "channel_backfill" for j in scheduler.scheduler_snapshot(db)["jobs"])
+
+    jobruns.start("channel_backfill", RunTrigger.AD_HOC, user.id, "UC_shown")
+    assert scheduler.scheduler_snapshot(db)["ad_hoc"][0]["running"] is True
+
+
 def _finished(db, job) -> list[JobRun]:
     return [r for r in _runs(db, job) if r.status != "running"]
 
 
+def test_an_ad_hoc_job_outside_the_named_list_is_refused(live_scheduler):
+    """The page names every ad-hoc job from AD_HOC_JOBS; one outside it would show as a bare id."""
+    with pytest.raises(KeyError):
+        scheduler.run_ad_hoc("unnamed_job", dict, actor_id=1, target="x")
+    assert live_scheduler.get_jobs() == []
+
+
 def test_a_second_ad_hoc_request_before_the_first_starts_is_that_same_run(
     db, make_user, live_scheduler
 ):