fix: clear subscriber map on shutdown

Even though it is not a case in the application, the interface could be
used externally

src/ahriman/core/status/event_bus.py

@@ -99,6 +99,7 @@ class EventBus(LazyLogging):
         async with self._lock:
             for subscription in self._subscribers.values():
                 subscription.queue.shutdown()
+            self._subscribers.clear()
 
     async def subscribe(self, topics: list[EventType] | None = None,
                         object_id: str | None = None) -> tuple[str, Queue[SSEvent]]:

src/ahriman/web/views/v1/auditlog/event_bus.py

@@ -101,7 +101,9 @@ class EventBusView(BaseView):
     @apidocs(
         tags=["Audit log"],
         summary="Live updates",
-        description="Stream live updates via SSE",
+        description="Stream live updates via SSE. Read-only users may subscribe only when all requested event filters "
+                    "belong to read-safe package and service status events; build log or unfiltered streams require "
+                    "full access. Streams are live-only and do not replay missed events after reconnect.",
         permission=UserAccess.Full,
         error_400_enabled=True,
         error_404_description="Repository is unknown",

tests/ahriman/core/status/test_event_bus.py

@@ -65,9 +65,10 @@ async def test_shutdown(event_bus: EventBus) -> None:
     """
     must shutdown all subscriber queues on shutdown
     """
-    _, queue = await event_bus.subscribe()
+    subscriber_id, queue = await event_bus.subscribe()
 
     await event_bus.shutdown()
+    assert subscriber_id not in event_bus._subscribers
     with pytest.raises(QueueShutDown):
         queue.get_nowait()