fix: show RDG flap badge on 302 and 303 events in SAC UI (0.20.5)

Seaca surfaced flap via Problems; the web UI only flagged 303 in DB and had
no visible label. Resolve flap pairs at read time and show badge plus qwinsta
on both sides of 302→303.

backend/app/schemas/list_models.py

@@ -71,6 +71,8 @@ class EventSummary(BaseModel):
     summary: str
     actor_user: str | None = None
     rdg_flap: bool = False
+    rdg_flap_pair_event_id: int | None = None
+    rdg_flap_qwinsta_event_id: int | None = None
 
     model_config = {"from_attributes": True}