docs: A-1 — sessions survive a JGroups partition but logout invalidation does not

Cutting TCP 7800 leaves cross-node refresh working (200), confirming sessions travel through PostgreSQL rather than the cluster transport. Logout is the opposite: the database row is deleted but the other node answers from its stale local cache, so the A-0 conclusion that invalidation rides the database is corrected here.

Two things the plan did not anticipate: a NetworkPolicy cannot sever an established connection because conntrack accepts it before policy evaluation, and Keycloak reports the partition through its readiness probe so the split node removes itself from the Service.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/evidence/a1-jgroups-transport-block/09-cross-node-under-partition.txt

@@ -0,0 +1,16 @@
+=== keycloak-0 헬스 상태 ===
+  keycloak-0 = 10.42.1.67   keycloak-1 = 10.42.0.35
+  PodReadyToStartContainers=True 
+  Initialized=True 
+  Ready=False ContainersNotReady
+  ContainersReady=False ContainersNotReady
+  PodScheduled=True 
+
+=== ★ 본 시험 — 분단 상태에서 교차 노드 세션이 되는가 ===
+  [1] keycloak-0 로그인          sid=nShl5TaBrZnKStDqaspjgmJB
+  [2] keycloak-1 에서 refresh     HTTP 200
+  [3] keycloak-1 에서 로그아웃    HTTP 204
+  [4] keycloak-0 에서 재갱신 시도 HTTP 200
+      (400 이면 무효화가 전파된 것)
+
+=== DB 세션 수 ===