feat: daily encrypted database backup to a bucket of its own

A backup service runs pg_dump every day at 03:00 Brasília, checks the archive,
encrypts it with age to a public key and uploads it with a token for that
bucket only. The server cannot read or delete backups: the private key stays
with the owner, the bucket's lifecycle rule expires copies and its lock stops
early deletion. Each run is recorded and shown on the Kanban's Integrations
tab. tests/backup_test.py backs up, restores into a scratch database and
compares the rows in CI. Setup and restore: docs/BACKUP.md.

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

app/api/operator.py

@@ -67,6 +67,16 @@ def freight_status():
             'production_days': freight.production_days}
 
 
+def backup_status(c):
+    """The latest database backup and the latest run, which may have failed."""
+    ok = c.execute('''SELECT finished_at,bytes FROM dtf_local.backups WHERE status='ok'
+        ORDER BY finished_at DESC LIMIT 1''').fetchone()
+    last = c.execute('SELECT finished_at,status,detail FROM dtf_local.backups ORDER BY finished_at DESC LIMIT 1').fetchone()
+    return {'last_ok': ok['finished_at'].isoformat() if ok else None, 'bytes': ok['bytes'] if ok else None,
+            'failed': last['detail'] if last and last['status'] == 'failed' else None,
+            'failed_at': last['finished_at'].isoformat() if last and last['status'] == 'failed' else None}
+
+
 @router.get('/api/operator/board')
 def board(user=Depends(operator)):
     with db.connect() as c:
@@ -97,9 +107,10 @@ def board(user=Depends(operator)):
         # Pagamentos tab pages through them until someone records a resolution.
         issues_total = c.execute('''SELECT count(*) AS n FROM dtf_local.payment_events
             WHERE (outcome LIKE 'refused%' OR outcome LIKE 'attention%') AND resolved_at IS NULL''').fetchone()['n']
+        backup = backup_status(c)
         return {'states': STATES, 'transitions': TRANSITIONS, 'back': BACK,
                 'orders': orders, 'payment_issues_total': issues_total, 'tiny': tiny_status(), 'operator': user,
-                'providers': {'payment': payment.name, 'freight': freight_status()}, 'environment': ENVIRONMENT,
+                'providers': {'payment': payment.name, 'freight': freight_status(), 'backup': backup}, 'environment': ENVIRONMENT,
                 'finished_shown': len(finished), 'finished_total': finished_total,
                 'quotes': [quote_view(c, q) for q in pending + approved],
                 'pending_total': pending_total, 'approved_total': approved_total}