argocd: keep label-based resource tracking explicitly

Argo CD 3.0 switches the default to annotation tracking. Per the 2.14->3.0
upgrade notes, a resource whose first sync after the switch is a deletion
gets orphaned instead of pruned. Pinning label tracking (the 2.14 default,
so no change today) keeps the upgrade to 3.x free of that; moving to
annotations can follow once everything runs 3.4.

argocd/overlays/argocd-cm.patch.yaml

@@ -7,6 +7,10 @@ metadata:
     app.kubernetes.io/part-of: argocd
 data:
   url: https://argocd.rubenhensen.nl
+  # Argo CD 3.0 defaults to annotation tracking. Stay on labels through the
+  # upgrade so no app loses track of its resources; switching is a
+  # separate step that needs every app synced once.
+  application.resourceTrackingMethod: label
   oidc.config: |
     name: Authentik
     issuer: https://authentik.rubenhensen.nl/application/o/argocd/