ci: add Hugo blog CI/CD to k3s

- Enable Gitea Container Registry
- Dockerfile: nginx:alpine serving hugo public/
- Gitea Actions: build & push image + deploy to k3s
- k8s manifests: namespace hugo, deployment, service, ingress
- RBAC: allow runner to update deployments in hugo ns
- .gitignore: add public/ (CI builds it)

deploy/hugo-rbac.yaml

@@ -0,0 +1,26 @@
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: hugo-deployer
+  namespace: hugo
+rules:
+- apiGroups: ["apps"]
+  resources: ["deployments"]
+  verbs: ["get", "list", "watch", "patch", "update"]
+- apiGroups: [""]
+  resources: ["pods"]
+  verbs: ["get", "list", "watch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: hugo-deployer-binding
+  namespace: hugo
+subjects:
+- kind: ServiceAccount
+  name: default
+  namespace: gitea-runner
+roleRef:
+  kind: Role
+  name: hugo-deployer
+  apiGroup: rbac.authorization.k8s.io