refactor(poimen): move frontend k8s manifests to poimen-frontend repo

- Remove Deployment/Service/NetworkPolicy from homelab (wrong place)
- Add k8s/apps/poimen-frontend/ with ingress only (edge concern, same as api-gw)
- Update 70-poimen.yaml: source 4 → poimen-frontend.git k8s/
                          source 5 → homelab k8s/apps/poimen-frontend/ (ingress)

k8s/argocd/apps/70-poimen.yaml

@@ -61,12 +61,17 @@ spec:
       targetRevision: main
       path: k8s/infra/poimen
 
-    # 4. Frontend — poimen.riotpiao.com (Deployment, Service, Ingress)
-    #    Manifests live in homelab so all infra is in one place (Q4: C).
-    #    Image tag managed by Image Updater above.
+    # 4. Frontend app manifests — Deployment, Service, NetworkPolicy.
+    #    Each repo owns its own k8s/ (same pattern as homelab-frontend for api-gw).
+    - repoURL: https://forgejo.riotpiao.com/riotpiao-poimen/poimen-frontend.git
+      targetRevision: main
+      path: k8s
+
+    # 5. Frontend ingress — poimen.riotpiao.com edge route.
+    #    Lives in homelab (same pattern as k8s/apps/api/ for api-gw).
     - repoURL: https://forgejo.riotpiao.com/riotpiao-poimen/homelab.git
       targetRevision: main
-      path: k8s/apps/poimen
+      path: k8s/apps/poimen-frontend
 
   destination:
     server: https://kubernetes.default.svc