docs: fill the untested items and record why the B layer has no graphs

The forward upgrade to 26.7.3 was zero downtime across 87 samples, and since databasechangelog stayed at 210 the rollback to 26.7.0 also succeeded, which narrows D-2's conclusion: rolling back fails when the schema moved, not because of the version number. The row count is the check.

Role changes never reach the upstream through request repetition; the session is a snapshot taken at login and only a new session picks up the new claim. Auditing the docs also surfaced that Prometheus scrapes only keycloak, kubelet, node-exporter and itself, so the B-layer experiments have no metrics to screenshot rather than missing screenshots.

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

docs/evidence/followup/02-d2-rollback-same-schema.txt

@@ -0,0 +1,20 @@
+=== ★ 가설: 스키마 변경이 없으면 롤백이 된다 (26.7.3 → 26.7.0) ===
+  시작: 15:25:08
+partitioned roll out complete: 2 new pods have been updated...
+  완료: 15:25:53
+
+  200 응답: 43 회 / 비200: 1
+
+  keycloak-0   1/1 Running restarts=0
+  keycloak-1   1/1 Running restarts=0
+  Keycloak 26.7.0
+  마이그레이션: 210
+  세션:        3
+=== 롤백 중 응답 시계열 (비200 위치) ===
+  200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 
+  200 200 200 200 000 200 200 200 200 200 200 200 200 200 200 200 200 200 200 200 
+  200 200 200 200 
+  비200 값: 000
+
+=== 대조: 정방향 업그레이드 때는 ===
+  200: 87 / 비200: 0