feat: add v2 stack (backend, runner, ui-v2) with release workflow

- backend/: Go API server and runner binaries with PocketBase + MinIO storage
- ui-v2/: SvelteKit frontend rewrite
- docker-compose-new.yml: compose file for the v2 stack
- .gitea/workflows/release-v2.yaml: CI/CD for backend, runner, and ui-v2 Docker Hub images
- scripts/pb-init.sh: migrate from wget to curl, add superuser bootstrap for fresh installs
- .env.example: document DOCKER_BUILDKIT=1 for Colima users

.gitea/workflows/release-v2.yaml

@@ -0,0 +1,163 @@
+name: Release / v2
+
+on:
+  push:
+    tags:
+      - "v*"
+
+concurrency:
+  group: ${{ gitea.workflow }}-${{ gitea.ref }}
+  cancel-in-progress: true
+
+jobs:
+  # ── backend: lint & test ─────────────────────────────────────────────────────
+  test-backend:
+    name: Test backend
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: backend/go.mod
+          cache-dependency-path: backend/go.sum
+
+      - name: go vet
+        working-directory: backend
+        run: go vet ./...
+
+      - name: Run tests
+        working-directory: backend
+        run: go test -short -race -count=1 -timeout=60s ./...
+
+  # ── ui-v2: type-check & build ────────────────────────────────────────────────
+  build-ui:
+    name: Build ui-v2
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ui-v2
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: npm
+          cache-dependency-path: ui-v2/package-lock.json
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Type check
+        run: npm run check
+
+      - name: Build
+        run: npm run build
+
+  # ── docker: backend ──────────────────────────────────────────────────────────
+  docker-backend:
+    name: Docker / backend
+    runs-on: ubuntu-latest
+    needs: [test-backend]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USER }}
+          password: ${{ secrets.DOCKER_TOKEN }}
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ secrets.DOCKER_USER }}/libnovel-backend
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=raw,value=latest
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: backend
+          target: backend
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          build-args: |
+            VERSION=${{ steps.meta.outputs.version }}
+            COMMIT=${{ gitea.sha }}
+
+  # ── docker: runner ───────────────────────────────────────────────────────────
+  docker-runner:
+    name: Docker / runner
+    runs-on: ubuntu-latest
+    needs: [test-backend]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USER }}
+          password: ${{ secrets.DOCKER_TOKEN }}
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ secrets.DOCKER_USER }}/libnovel-runner
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=raw,value=latest
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: backend
+          target: runner
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          build-args: |
+            VERSION=${{ steps.meta.outputs.version }}
+            COMMIT=${{ gitea.sha }}
+
+  # ── docker: ui-v2 ────────────────────────────────────────────────────────────
+  docker-ui:
+    name: Docker / ui-v2
+    runs-on: ubuntu-latest
+    needs: [build-ui]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Log in to Docker Hub
+        uses: docker/login-action@v3
+        with:
+          username: ${{ secrets.DOCKER_USER }}
+          password: ${{ secrets.DOCKER_TOKEN }}
+
+      - name: Docker meta
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ secrets.DOCKER_USER }}/libnovel-ui-v2
+          tags: |
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=raw,value=latest
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: ui-v2
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          build-args: |
+            BUILD_VERSION=${{ steps.meta.outputs.version }}
+            BUILD_COMMIT=${{ gitea.sha }}