fix(longhorn): clear permanent OutOfSync on longhorn-config

StorageClass.parameters is immutable and mkfsParams was added after creation,
so every sync failed. Replace=true recreates it instead of patching. Existing
volumes keep their format; only new ones get mkfsParams.

Longhorn names its own disk key and writes storageReserved into it, so git's
default-disk never matched and selfHeal kept trying to add a second disk on the
same path. Dropped spec.disks from git, added ignoreDifferences.

k8s/argocd/apps/10-storage-observability.yaml

@@ -72,6 +72,14 @@ spec:
   destination:
     server: https://kubernetes.default.svc
     namespace: longhorn-system
+  # Longhorn writes disk state back into its own Node CRs — the disk key it
+  # generates, storageReserved, diskType, evictionRequested. Git declares only
+  # allowScheduling; without this the controller's writes read as drift forever.
+  ignoreDifferences:
+    - group: longhorn.io
+      kind: Node
+      jsonPointers:
+        - /spec/disks
   syncPolicy:
     automated:
       prune: true