ci: publish docker image to GHCR and create GitHub release on tag

.github/workflows/release.yml

@@ -0,0 +1,79 @@
+name: release
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+permissions:
+  contents: write
+  packages: write
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  docker:
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    outputs:
+      digest: ${{ steps.build.outputs.digest }}
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GHCR
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Image metadata
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=ref,event=tag
+            type=semver,pattern={{version}}
+            type=semver,pattern={{major}}.{{minor}}
+            type=raw,value=latest
+
+      - name: Build and push
+        id: build
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          file: Dockerfile
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+  release:
+    runs-on: ubuntu-latest
+    needs: docker
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Create GitHub release
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          set -euo pipefail
+          TAG="${GITHUB_REF_NAME}"
+          IMAGE="${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${TAG}"
+          DIGEST="${{ needs.docker.outputs.digest }}"
+          PREV_TAG="$(git tag --sort=-creatordate | grep -v "^${TAG}$" | head -n1 || true)"
+          ARGS=( "$TAG" --title "$TAG" --generate-notes \
+            --notes "Container image: \`${IMAGE}\` (digest \`${DIGEST}\`)" )
+          if [ -n "$PREV_TAG" ]; then
+            ARGS+=( --notes-start-tag "$PREV_TAG" )
+          fi
+          gh release create "${ARGS[@]}"