fix: make helm-based addon kustomizations health-check HelmReleases only

These addon Kustomizations were using wait=true, which made Flux treat transient
HelmRepository fetch timeouts as addon failures even when the HelmRelease and
runtime workloads were healthy. Switch the affected Kustomizations to explicit
HelmRelease healthChecks so readiness reflects the actual deployed platform
state instead of repository fetch flakiness.

infrastructure/addons/kustomization-nfs-storage.yaml

@@ -10,6 +10,11 @@ spec:
     kind: GitRepository
     name: platform
   path: ./infrastructure/addons/nfs-storage
-  wait: true
+  wait: false
+  healthChecks:
+    - apiVersion: helm.toolkit.fluxcd.io/v2
+      kind: HelmRelease
+      name: nfs-subdir-external-provisioner
+      namespace: flux-system
   timeout: 10m
   suspend: false

infrastructure/addons/kustomization-observability.yaml

@@ -14,6 +14,19 @@ spec:
     - name: addon-external-secrets
     - name: addon-tailscale-operator
     - name: addon-tailscale-proxyclass
-  wait: true
+  wait: false
+  healthChecks:
+    - apiVersion: helm.toolkit.fluxcd.io/v2
+      kind: HelmRelease
+      name: kube-prometheus-stack
+      namespace: flux-system
+    - apiVersion: helm.toolkit.fluxcd.io/v2
+      kind: HelmRelease
+      name: loki
+      namespace: flux-system
+    - apiVersion: helm.toolkit.fluxcd.io/v2
+      kind: HelmRelease
+      name: promtail
+      namespace: flux-system
   timeout: 5m
   suspend: false

infrastructure/addons/kustomization-rancher-backup.yaml

@@ -16,3 +16,9 @@ spec:
   dependsOn:
     - name: addon-external-secrets
     - name: addon-rancher
+  wait: false
+  healthChecks:
+    - apiVersion: helm.toolkit.fluxcd.io/v2
+      kind: HelmRelease
+      name: rancher-backup
+      namespace: flux-system

infrastructure/addons/kustomization-rancher.yaml

@@ -18,3 +18,9 @@ spec:
     - name: addon-tailscale-proxyclass
     - name: addon-external-secrets
     - name: addon-cert-manager
+  wait: false
+  healthChecks:
+    - apiVersion: helm.toolkit.fluxcd.io/v2
+      kind: HelmRelease
+      name: rancher
+      namespace: flux-system