chore: retrigger isolated CI builds for users, social-media-managers (again)

Both still on stale bad digests after the previous retrigger. Old replicas
continue serving traffic throughout, so no outage.

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

apps/social_media_managers/src/main.rs

@@ -1,3 +1,4 @@
+// retrigger-build-marker-6
 // retrigger-build-marker-5
 // retrigger-build-marker-4
 #![allow(dead_code)]

apps/users/src/main.rs

@@ -1,3 +1,4 @@
+// retrigger-build-marker-6
 // retrigger-build-marker-4
 #![allow(dead_code)]