GitLab cross-site replication Phase 2a (corrected): ignoreDifferences approach

The CONFIG_TEMPLATE_DIRECTORY redirect from the previous commit doesn't
work - confirmed live that extraVolumes is a dead values key for the
Praefect subchart specifically (its statefulset.yaml never calls the
gitlab.extraVolumes helper in its volumes: list, only volumeMounts
calls the corresponding helper - a real chart limitation, not a config
mistake). A dangling volumeMount with no matching volume would have
failed to schedule.

Real fix: ignoreDifferences on ConfigMap gitlab-praefect's data field
(argocd-apps/apps/gitlab.yaml) lets Helm create the object normally
while ArgoCD stops reconciling its content afterward - the actual
config gets kubectl-patched onto the live object directly.
praefect-ha-configmap.yaml is now a git-tracked reference/documentation
copy (deployed under its own harmless name) rather than something
Helm/ArgoCD wires in on its own.

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

argocd-apps/apps/gitlab.yaml

@@ -33,6 +33,19 @@ spec:
       jsonPointers:
         - /spec/ports
         - /spec/selector
+    # GitLab cross-site replication (see
+    # /home/scooby/.claude/plans/jiggly-snacking-iverson.md) - the chart
+    # has no mechanism to register an externally-hosted (VPS) Gitaly node
+    # into Praefect's virtual storage. Lets the live ConfigMap's `data`
+    # be kubectl-patched directly (see apps/gitlab/manifests/
+    # praefect-ha-configmap.yaml for the content + patch command) without
+    # ArgoCD reverting it on the next sync - Helm still creates the
+    # object and everything else about it stays normally managed.
+    - group: ""
+      kind: ConfigMap
+      name: gitlab-praefect
+      jsonPointers:
+        - /data
   syncPolicy:
     automated:
       prune: true