ci: fix Dockerfile for Rust + correct Forgejo runner labels

Issues fixed:
- Dockerfile was Python/Uvicorn (wrong for Rust project)
  - Changed to multi-stage Rust build (rust:1.81 → debian:bookworm-slim)
  - Correct binary name: mem (not mem-cli)
  - Added proper health check with curl

- CI runner labels were incorrect (rust/golang → docker)
  - Changed test job to: runs-on: docker with rust:1.81-bookworm container
  - Changed build job to: runs-on: docker

- Docker build config was broken
  - Switched to standard actions (setup-buildx, login, build-push)
  - Added Cargo caching (registry, git, target)
  - Added format + clippy checks
  - Simplified login/build/push flow

Ready for CI/CD pipeline restart.

.forgejo/workflows/build.yaml

@@ -13,46 +13,54 @@ env:
 jobs:
   test:
     name: Test
-    runs-on: rust
-    container: rust:1-bookworm
+    runs-on: docker
+    container:
+      image: rust:1.81-bookworm
     steps:
-      - name: Install node (required by JS-based actions)
-        run: apt-get update && apt-get install -y --no-install-recommends nodejs
+      - name: Checkout
+        uses: actions/checkout@v4
 
-      - uses: actions/checkout@v4
-
-      - name: Cache cargo
+      - name: Cache cargo registry
         uses: actions/cache@v4
         with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-            target
-          key: cargo-${{ runner.os }}-${{ hashFiles('**/Cargo.lock') }}
+          path: ~/.cargo/registry
+          key: cargo-registry-${{ hashFiles('**/Cargo.lock') }}
           restore-keys: |
-            cargo-${{ runner.os }}-
+            cargo-registry-
+
+      - name: Cache cargo index
+        uses: actions/cache@v4
+        with:
+          path: ~/.cargo/git
+          key: cargo-git-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            cargo-git-
+
+      - name: Cache build target
+        uses: actions/cache@v4
+        with:
+          path: target
+          key: cargo-target-${{ hashFiles('**/Cargo.lock') }}
+          restore-keys: |
+            cargo-target-
 
       - name: Run tests
-        run: cargo test --all
+        run: cargo test --all --verbose
+
+      - name: Check formatting
+        run: cargo fmt --all -- --check
+
+      - name: Run clippy
+        run: cargo clippy --all -- -D warnings
 
   build:
-    name: Build and push image
-    runs-on: golang
+    name: Build and Push Image
+    runs-on: docker
     needs: test
     if: github.event_name == 'push' && github.ref == 'refs/heads/main'
-    container:
-      image: docker:27-cli
-      volumes:
-        - /docker-certs/client:/docker-certs/client:ro
-    env:
-      DOCKER_HOST: tcp://localhost:2376
-      DOCKER_TLS_VERIFY: "1"
-      DOCKER_CERT_PATH: /docker-certs/client
     steps:
-      - name: Install node (required by JS-based actions)
-        run: apk add --no-cache nodejs git
-
-      - uses: actions/checkout@v4
+      - name: Checkout
+        uses: actions/checkout@v4
 
       - name: Get short SHA
         id: sha
@@ -60,21 +68,23 @@ jobs:
           SHORT_SHA=$(git rev-parse --short HEAD)
           echo "short_sha=${SHORT_SHA}" >> $GITHUB_OUTPUT
 
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
       - name: Registry login
-        run: |
-          echo "${REGISTRY_PAT}" | docker login "${REGISTRY}" \
-            --username rock --password-stdin
-        env:
-          REGISTRY_PAT: ${{ secrets.REGISTRY_PAT }}
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: rock
+          password: ${{ secrets.REGISTRY_PAT }}
 
-      - name: Build
-        run: |
-          docker build \
-            -t "${IMAGE}:${{ steps.sha.outputs.short_sha }}" \
-            -t "${IMAGE}:latest" \
-            .
-
-      - name: Push
-        run: |
-          docker push "${IMAGE}:${{ steps.sha.outputs.short_sha }}"
-          docker push "${IMAGE}:latest"
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: |
+            ${{ env.IMAGE }}:${{ steps.sha.outputs.short_sha }}
+            ${{ env.IMAGE }}:latest
+          cache-from: type=gha
+          cache-to: type=gha,mode=max