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/tests/test_health.py

@@ -4,6 +4,6 @@ from app.version import APP_NAME, APP_VERSION, APP_VERSION_LABEL
 
 
 def test_version_constants():
-    assert APP_VERSION == "0.9.12"
+    assert APP_VERSION == "0.9.13"
     assert APP_NAME == "Security Alert Center"
-    assert APP_VERSION_LABEL == "Security Alert Center v.0.9.12"
+    assert APP_VERSION_LABEL == "Security Alert Center v.0.9.13"