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-deployment.yaml

@@ -0,0 +1,41 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: hugo-blog
+  namespace: hugo
+  labels:
+    app: hugo-blog
+spec:
+  replicas: 1
+  strategy:
+    type: RollingUpdate
+    rollingUpdate:
+      maxUnavailable: 0
+      maxSurge: 1
+  selector:
+    matchLabels:
+      app: hugo-blog
+  template:
+    metadata:
+      labels:
+        app: hugo-blog
+    spec:
+      containers:
+      - name: nginx
+        image: git.luochen570.cn/luochen570/hugo-blog:latest
+        imagePullPolicy: Always
+        ports:
+        - containerPort: 80
+          name: http
+        readinessProbe:
+          httpGet:
+            path: /
+            port: 80
+          initialDelaySeconds: 5
+          periodSeconds: 10
+        livenessProbe:
+          httpGet:
+            path: /
+            port: 80
+          initialDelaySeconds: 15
+          periodSeconds: 20