feat: RDG session flap rule, qwinsta/logoff queue and dashboard UI (0.9.13)

Detect 302→303 within 1–10s, Problem with 30s dedup, rdg_flap flag.
Agent command poll API, admin qwinsta/logoff from Overview. Migration 016.

backend/app/services/event_summary.py

@@ -1,6 +1,7 @@
 from app.models.event import Event
 from app.schemas.list_models import EventSummary
 from app.services.event_actor_user import extract_event_actor_user
+from app.services.rdg_session_flap import event_has_rdg_flap
 
 
 def event_to_summary(event: Event) -> EventSummary:
@@ -20,4 +21,5 @@ def event_to_summary(event: Event) -> EventSummary:
         title=event.title,
         summary=event.summary,
         actor_user=extract_event_actor_user(event.type, event.details),
+        rdg_flap=event_has_rdg_flap(event),
     )