feat(523): the backup job - an hourly tick that runs at the chosen hour, Back up now, and the last 30 runs

services/backup_job.py reads its config when it fires, so startup reads
nothing (#4181) and a changed hour needs no reschedule. A run is held to
a 60-minute deadline (a hung NFS mount would otherwise hold the lock and
skip every later backup), never runs twice at once, and keeps its outcome
- file, size, duration, or the reason in words - in the bounded
backup_runs setting, which no backup carries. summarise() gives the page
its verdict: overdue when on and no success for 26h.

Admin API: GET/PUT /api/admin/backups, POST /backups/check (tests unsaved
form values, 45s deadline), POST /backups/run (202, background).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/scribe/app.py

@@ -304,6 +304,11 @@ def create_app() -> Quart:
                 asyncio.get_running_loop(), await get_maintenance_hour()
             )
 
+            # Scheduled backups (milestone 523). An hourly tick that reads its
+            # config when it fires, so starting it reads nothing here (#4181).
+            from scribe.services.backup_job import start_backup_scheduler
+            start_backup_scheduler(asyncio.get_running_loop())
+
             # Diagnostic instrumentation — heartbeat, signal handlers, asyncio
             # exception hook. Cheap (~1 log line/min), high diagnostic value when
             # the app crashes mysteriously. See services/diagnostics.py.
@@ -330,6 +335,8 @@ def create_app() -> Quart:
             stop_db_maintenance_scheduler,
         )
         stop_db_maintenance_scheduler()
+        from scribe.services.backup_job import stop_backup_scheduler
+        stop_backup_scheduler()
         from scribe.services.diagnostics import stop_diagnostics
         stop_diagnostics()