feature: Add local subscription notification worker

tests/test_subscription_notification_worker.py

@@ -0,0 +1,60 @@
+from datetime import datetime, timedelta, timezone
+from types import SimpleNamespace
+
+from bot.services.subscription_notification_worker import SubscriptionNotificationWorker
+
+
+def _worker(**overrides):
+    settings = SimpleNamespace(
+        SUBSCRIPTION_NOTIFY_DAYS_BEFORE=3,
+        SUBSCRIPTION_NOTIFY_HOURS_BEFORE=3,
+        SUBSCRIPTION_NOTIFY_ON_EXPIRE=True,
+        SUBSCRIPTION_NOTIFY_AFTER_EXPIRE=True,
+        SUBSCRIPTION_NOTIFICATION_WORKER_TICK_SECONDS=300,
+        **overrides,
+    )
+    return SubscriptionNotificationWorker(
+        settings=settings,
+        session_factory=object(),
+        bot=object(),
+        i18n=object(),
+        panel_service=object(),
+        subscription_service=object(),
+    )
+
+
+def _sub(end_date):
+    return SimpleNamespace(end_date=end_date)
+
+
+def test_stage_prefers_hour_reminder_over_day_backlog():
+    now = datetime(2026, 5, 28, 12, tzinfo=timezone.utc)
+    stage = _worker().stage_for_subscription(_sub(now + timedelta(hours=2, minutes=30)), now)
+
+    assert stage.key == "before_3h"
+    assert stage.message_key == "subscription_hours_notification"
+    assert stage.hours_before == 3
+
+
+def test_stage_uses_most_imminent_day_reminder():
+    now = datetime(2026, 5, 28, 12, tzinfo=timezone.utc)
+    stage = _worker().stage_for_subscription(_sub(now + timedelta(hours=23)), now)
+
+    assert stage.key == "before_1d"
+    assert stage.message_key == "subscription_24h_notification"
+
+
+def test_stage_sends_expired_during_first_day_after_end():
+    now = datetime(2026, 5, 28, 12, tzinfo=timezone.utc)
+    stage = _worker().stage_for_subscription(_sub(now - timedelta(hours=1)), now)
+
+    assert stage.key == "expired"
+    assert stage.message_key == "subscription_expired_notification"
+
+
+def test_stage_sends_yesterday_notice_only_after_first_day():
+    now = datetime(2026, 5, 28, 12, tzinfo=timezone.utc)
+    stage = _worker().stage_for_subscription(_sub(now - timedelta(hours=25)), now)
+
+    assert stage.key == "expired_24h_after"
+    assert stage.message_key == "subscription_expired_yesterday_notification"