docs: C-2 — nothing propagates because nobody implemented the receiving end

Neither client had a backchannel logout URL and the BFF has no oidcLogout configuration, so the three candidate paths all answer 302, which is the authentication redirect rather than a handler. Setting the URL on the identity provider alone changed nothing: with a live session, logging the user out emptied the Keycloak side and left the Redis session untouched.

Reachability is not the blocker here, since a Keycloak pod fetches the app's public URL with a 200, but that is a property of this tailnet split-DNS lab and is the assumption most likely to fail in production, where it fails silently.

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

.playwright-mcp/page-2026-09-04T05-55-08-213Z.yml

@@ -0,0 +1,16 @@
+- generic [ref=f54e3]:
+  - banner [ref=f54e4]:
+    - generic [ref=f54e5]: keycloak-patterns
+  - main [ref=f54e6]:
+    - heading "Sign in to your account" [level=1] [ref=f54e8]
+    - generic [ref=f54e12]:
+      - generic [ref=f54e13]:
+        - generic [ref=f54e14]: Username or email
+        - textbox "Username or email" [ref=f54e17]
+      - generic [ref=f54e18]:
+        - generic [ref=f54e19]: Password
+        - generic [ref=f54e21]:
+          - textbox "Password" [ref=f54e24]
+          - button "Show password" [ref=f54e26] [cursor=pointer]:
+            - generic [aria-hidden] [ref=f54e27]: 
+      - button "Sign In" [ref=f54e30] [cursor=pointer]