feat: implement Havenllo single-board kanban (Go+SQLite backend, Preact/Vite frontend)

- Single fixed 'Haven' board: lists (To do/In progress/Done) + cards, no multi-board
- Go 1.24 backend, CGO-free modernc.org/sqlite, embedded SPA, REST /api
- Preact + Vite + TS frontend, native HTML5 drag-and-drop, optimistic UI, dark Haven theme
- PVC (nfs-client) for SQLite, root container on NFS, simple nginx ingress havenllo.haven
- Dockerfile multi-arch build, Gitea CI via pipeline-actions@main

.gitea/workflows/main.yaml

@@ -0,0 +1,59 @@
+name: Build and deploy Havenllo
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+jobs:
+  verify:
+    name: Verify Go and frontend
+    runs-on: runner-slim-amd64
+    steps:
+      - name: Check out source
+        uses: actions/checkout@v4
+      - name: Test Go
+        run: go test ./...
+      - name: Install frontend dependencies
+        working-directory: web
+        run: npm ci
+      - name: Build frontend
+        working-directory: web
+        run: npm run build
+      - name: Validate Kubernetes manifest
+        run: |
+          if command -v kubectl >/dev/null 2>&1; then
+            kubectl apply --dry-run=client -f deploy/havenllo.yaml
+          fi
+  build:
+    name: Build and push image
+    needs: verify
+    runs-on: runner-slim-amd64
+    steps:
+      - name: Check out source
+        uses: actions/checkout@v4
+      - name: Build and push multi-architecture image
+        uses: https://git.ivanch.me/ivanch/pipeline-actions/build-and-push@main
+        with:
+          image: git.ivanch.me/ivanch/havenllo
+          image_tag: latest
+          registry_password: ${{ secrets.REGISTRY_PASSWORD }}
+          ssh_key: ${{ secrets.SSH_KEY_DOCKERBUILD }}
+  deploy:
+    name: Apply and restart Havenllo
+    needs: build
+    runs-on: runner-slim-amd64
+    steps:
+      - name: Check out source
+        uses: actions/checkout@v4
+      - name: Apply Kubernetes manifest
+        uses: https://git.ivanch.me/ivanch/pipeline-actions/kubectl-apply@main
+        with:
+          manifest: deploy/havenllo.yaml
+          kube_config: ${{ secrets.KUBE_CONFIG }}
+      - name: Restart deployment
+        uses: https://git.ivanch.me/ivanch/pipeline-actions/deploy-restart@main
+        with:
+          deployment_name: havenllo
+          namespace: default
+          kube_config: ${{ secrets.KUBE_CONFIG }}