fix: Persist the Azure digest deadline receipt

docs/unified-daily-notification.md

@@ -336,6 +336,13 @@ stored delivery receipt; it does not recollect late candidates or prove receiver
 receipt. Do not postpone the central read or widen the business window to hide
 late producer jobs.
 
+The Azure deadline check also saves its first result under
+`<recipient-scope>/deadline-checks/<report-date>.json` within the delivery
+prefix. The record is create-only. It can be read after the job's console
+logs expire and records the check result, the original slot and check time.
+A retry keeps the first recorded result. The check reads the delivery
+record and never sends a notification or modifies that record.
+
 Each expected producer target has an archive-only entrypoint,
 `python -m scripts.publish_digest_before_read`, in its platform repository.
 The proposed trigger is a dedicated Cloud Run Job at 06:10 Asia/Shanghai,

python/scripts/azure_timer_digest.py

@@ -58,8 +58,32 @@ def execute_scheduled(scheduled, configuration, store, send, *, now=core.utc_now
 
 def _execute_validated(scheduled, configuration, store, send, *, now, platform_config, provenance):
     report_date, day, check = core.business_slot(scheduled)
-    return core.execute_slot(
+    status, result = core.execute_slot(
         report_date, day, check,
         {'scheduled_at': scheduled.isoformat(), 'trigger_provenance': provenance},
         configuration, store, send, now=now, platform_config=platform_config,
     )
+    if result.get('phase') != 'deadline_check':
+        return status, result
+    key = f'{configuration.recipient_scope}/deadline-checks/{report_date.isoformat()}.json'
+    receipt = {
+        'schema_version': 'qsl.daily_digest_deadline_check.v1',
+        'report_date': report_date.isoformat(),
+        'business_day': day,
+        'scheduled_at': scheduled.isoformat(),
+        'checked_at': now().isoformat(),
+        'delivery': result['delivery'],
+        'trigger_provenance': provenance,
+    }
+    try:
+        created, existing = store.reserve(key, receipt)
+        if not created:
+            identity_fields = ('schema_version', 'report_date', 'business_day')
+            if (not isinstance(existing, dict)
+                or any(existing.get(field) != receipt[field] for field in identity_fields)
+                or existing.get('delivery') not in ('confirmed', 'receipt_unverified')):
+                raise core.StoreUnavailable()
+            result = {**result, 'delivery': existing['delivery']}
+    except core.StoreUnavailable:
+        return 503, {**result, 'deadline_receipt': 'unverified'}
+    return status, {**result, 'deadline_receipt': 'recorded' if created else 'already_recorded'}

python/tests/test_azure_timer_digest.py

@@ -73,3 +73,37 @@ def test_container_window_supplies_original_time_at_the_boundary(self):
                 ValueError, 'unverified_sliding_window'
             ):
                 window_slot(bad_start, bad_end, 86400, NOW)
+
+    def test_deadline_receipt_is_separate_create_only_and_keeps_first_result(self):
+        store, send = Mock(), Mock()
+        store.delivery.return_value = {
+            'report_date': '2026-11-10', 'business_day': '2026-11-09',
+            'recipient_scope': 'synthetic', 'delivery': 'accepted', 'late': False,
+        }
+        configuration = Mock(recipient_scope='synthetic', cutover_date='2026-11-10', enabled=True)
+        slot = datetime.fromisoformat('2026-11-09T23:30:00Z')
+        store.reserve.return_value = (True, 1)
+        code, result = execute_scheduled(slot, configuration, store, send, now=lambda: NOW)
+        self.assertEqual((code, result['delivery'], result['deadline_receipt']), (200, 'confirmed', 'recorded'))
+        key, receipt = store.reserve.call_args.args
+        self.assertEqual(key, 'synthetic/deadline-checks/2026-11-10.json')
+        self.assertEqual(receipt['delivery'], 'confirmed')
+        store.delivery.assert_called_once_with('synthetic/2026-11-10.json')
+
+        store.reserve.return_value = (False, {**receipt, 'delivery': 'receipt_unverified'})
+        code, result = execute_scheduled(slot, configuration, store, send, now=lambda: NOW)
+        self.assertEqual((code, result['delivery'], result['deadline_receipt']),
+                         (200, 'receipt_unverified', 'already_recorded'))
+        store.finish.assert_not_called()
+        send.assert_not_called()
+
+    def test_deadline_receipt_storage_failure_retries_check_without_sending(self):
+        store, send = Mock(), Mock()
+        store.delivery.return_value = None
+        store.reserve.side_effect = core.StoreUnavailable()
+        configuration = Mock(recipient_scope='synthetic', cutover_date='2026-11-10', enabled=True)
+        slot = datetime.fromisoformat('2026-11-09T23:30:00Z')
+        code, result = execute_scheduled(slot, configuration, store, send, now=lambda: NOW)
+        self.assertEqual((code, result['delivery'], result['deadline_receipt']),
+                         (503, 'receipt_unverified', 'unverified'))
+        send.assert_not_called()