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)

.gitea/workflows/deploy.yml

@@ -0,0 +1,54 @@
+name: Deploy Hugo Blog to k3s
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+env:
+  REGISTRY: git.luochen570.cn
+  IMAGE: luochen570/hugo-blog
+
+jobs:
+  build-and-deploy:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Hugo
+        uses: peaceiris/actions-hugo@v3
+        with:
+          hugo-version: '0.161.1'
+          extended: true
+
+      - name: Hugo Build
+        run: hugo --minify
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Login to Gitea Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: luochen570
+          password: ${{ secrets.REGISTRY_TOKEN }}
+
+      - name: Build and Push Docker Image
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          tags: |
+            ${{ env.REGISTRY }}/${{ env.IMAGE }}:${{ github.sha }}
+            ${{ env.REGISTRY }}/${{ env.IMAGE }}:latest
+
+      - name: Deploy to k3s
+        run: |
+          kubectl set image deployment/hugo-blog -n hugo \
+            nginx=${{ env.REGISTRY }}/${{ env.IMAGE }}:${{ github.sha }}