fix(activity): a run nothing here has open reads as interrupted, a rollback sums a stopped run's spend

- The scheduler keeps one registry of the runs this process has open, for the interval jobs and the
  ad-hoc runs alike. A row the table still says is `running` but no run here has open (its outcome
  failed to write) reads as interrupted, as the next start's sweep will close it: no pulsing dot
  beside "No run recorded yet".
- Migration 0109's downgrade sums a still-running run's quota events into its spend before the link
  to them is dropped, as the startup sweep would.
- A test holds that a dialog closing onto the same address leaves an open log line open.

backend/tests/test_migration_0109.py

@@ -131,6 +131,13 @@ def test_a_down_and_up_round_trip_keeps_every_run(db, make_user):
             ),
             {"u": uid},
         )
+        # What the run caught mid-way had spent: only its quota rows know it yet.
+        conn.execute(
+            text(
+                "INSERT INTO quota_events (action, units, job_run_id)"
+                " SELECT 'videos.list', 7, id FROM job_runs WHERE job = 'maintenance'"
+            )
+        )
     cfg = Config("alembic.ini")
     command.downgrade(cfg, "0108_folder_links")
     command.upgrade(cfg, "head")
@@ -141,6 +148,9 @@ def test_a_down_and_up_round_trip_keeps_every_run(db, make_user):
         kept = conn.execute(
             text("SELECT quota_units, finished_at - started_at FROM job_runs WHERE job = 'enrich'")
         ).one()
+        stopped = conn.execute(
+            text("SELECT quota_units FROM job_runs WHERE job = 'maintenance'")
+        ).scalar()
         stranded = conn.execute(
             text("SELECT count(*) FROM audit_log WHERE action = 'job_run'")
         ).scalar()
@@ -151,4 +161,5 @@ def test_a_down_and_up_round_trip_keeps_every_run(db, make_user):
         ("enrich", "manual", None, None, "ok"),
     ]
     assert tuple(kept) == (42, timedelta(minutes=30))
+    assert stopped == 7
     assert stranded == 0