feat: register multus Argo CD Application (manual sync)

Points at manifests/multus/ — deliberately no syncPolicy.automated, so
app-of-apps picking this up only registers the Application; nothing
under it deploys until selectively synced by hand.

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

argocd/apps/multus.yaml

@@ -0,0 +1,27 @@
+# Multus + VLAN 50 NAD + canary for VPN VLAN 50 (plan.md Phase 4/5).
+#
+# Deliberately manual sync (no syncPolicy.automated) — unlike this repo's
+# other Applications, every resource here (Multus DaemonSet, NAD, canary
+# pod) needs an explicit human go-ahead before it ever touches the
+# cluster, and staying manual means merging this file to main does NOT
+# by itself deploy anything. Use selective sync (argocd app sync multus
+# --resource <group:kind:name>, or the UI's per-resource sync) to apply
+# 00/01/02 (Multus itself), verify, then 10 (the NAD), verify, then 20
+# (the canary) only once the user has separately approved running it.
+apiVersion: argoproj.io/v1alpha1
+kind: Application
+metadata:
+  name: multus
+  namespace: argocd
+spec:
+  project: default
+  source:
+    repoURL: https://gitea.nik4nao.com/nik/homelab.git
+    targetRevision: main
+    path: manifests/multus
+  destination:
+    server: https://kubernetes.default.svc
+    namespace: kube-system
+  syncPolicy:
+    syncOptions:
+      - CreateNamespace=true