fix(activity): runs keep their true outcome and spend, the page reaches every kept row, a closing dialog leaves the server log alone

Backend
- A run's outcome write sits outside the job's own try: a database blip after a run that
  succeeded no longer records it as failed (the row waits for the next start's sweep).
- An interrupted run keeps what it spent (the sweep sums its quota rows, as finish does).
- The Scheduler's ad-hoc row says running while any backfill runs, not only the newest.
- recent_runs reads each job's last runs off its index instead of ranking the whole table.
- An interval change is stored with its audit row in one transaction, then rescheduled.
- One API instance per database is the stated contract (.env.example, jobruns).
- Turning full history on for a channel already complete records no run.
- Migration 0109 round-trips interrupted and ad-hoc runs; the run words' DB CHECKs are
  test-held to the enums; the account filter is one helper for the four activity reads.
- An audit row says how many of its request's log lines are still kept.

Frontend
- An "All" period reaches every row still kept (runs and admin actions outlive 90 days).
- Back/Forward is followed in place by the server log: a closing dialog no longer turns
  Live off; a pivot still opens a fresh log.
- Runs moved over from the audit log read their one-liner in the reader's language.
- Filter choices or accounts that failed to load say so beside the filters, with a retry.
- An old server-log link keeps its account, text and range; a remembered retired page
  opens its tab.
- A request whose lines are gone says so instead of linking to an empty list.
- The log lines and the history rows share one row frame, and the server log one list
  frame with the other tabs; an empty list is announced; each day's quota is readable.

backend/app/routes/scheduler.py

@@ -17,8 +17,9 @@ from app.scheduler import (
     JOB_INTERVALS,
     MAX_INTERVAL,
     MIN_INTERVAL,
-    apply_interval,
+    reschedule,
     scheduler_snapshot,
+    stage_interval,
     trigger_all,
     trigger_job,
 )
@@ -42,14 +43,14 @@ def set_job_interval(
     admin: User = Depends(admin_user),
     db: Session = Depends(get_db),
 ) -> dict:
-    """Change how often a scheduler job runs (minutes). Persisted as an override and applied
-    to the live scheduler immediately."""
+    """Change how often a scheduler job runs (minutes). Stored as an override together with its
+    audit row, then applied to the live scheduler."""
     if job_id not in JOB_INTERVALS:
         raise not_found("job")
     minutes = body.interval_minutes
     if not (MIN_INTERVAL <= minutes <= MAX_INTERVAL):
         raise refused(400, "invalid_interval", min=MIN_INTERVAL, max=MAX_INTERVAL)
-    applied = apply_interval(db, job_id, minutes)
+    applied = stage_interval(db, job_id, minutes)
     audit.record(
         db,
         admin.id,
@@ -60,6 +61,7 @@ def set_job_interval(
         after={"interval_minutes": applied},
     )
     db.commit()
+    reschedule(job_id, applied)
     return {"ok": True, "id": job_id, "interval_minutes": applied}