feature(ci): add actions workflow to publish Docker image to GHCR

.github/workflows/publish-image.yml

@@ -0,0 +1,105 @@
+name: Build and publish container image to GHCR
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - 'v*'
+  release:
+    types: [published]
+  pull_request:
+  workflow_dispatch:
+
+concurrency:
+  group: publish-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+  packages: write
+  id-token: write
+  attestations: write
+
+jobs:
+  build-and-push:
+    name: Build and push image
+    runs-on: ubuntu-latest
+    timeout-minutes: 45
+    env:
+      REGISTRY: ghcr.io
+      IMAGE_NAME: ${{ github.repository }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up QEMU (multi-arch)
+        uses: docker/setup-qemu-action@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Log in to GHCR
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Compute canonical image name (lowercase)
+        id: vars
+        shell: bash
+        run: |
+          set -eu
+          # Use provided IMAGE_NAME or default to the GitHub repository path
+          IMAGE_REF="${IMAGE_NAME:-$GITHUB_REPOSITORY}"
+          # Lowercase image ref for GHCR compatibility
+          CANONICAL_IMAGE="${REGISTRY}/${IMAGE_REF,,}"
+          echo "canonical=${CANONICAL_IMAGE}" >> "$GITHUB_OUTPUT"
+
+      - name: Extract Docker metadata (tags, labels)
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ steps.vars.outputs.canonical }}
+          tags: |
+            type=ref,event=branch
+            type=ref,event=tag
+            type=sha,format=short,prefix=sha-
+            type=semver,pattern={{version}},enable=${{ startsWith(github.ref, 'refs/tags/v') }}
+            type=semver,pattern={{major}}.{{minor}},enable=${{ startsWith(github.ref, 'refs/tags/v') }}
+            type=semver,pattern={{major}},enable=${{ startsWith(github.ref, 'refs/tags/v') }}
+          flavor: |
+            latest=auto
+
+      - name: Build and push
+        id: build
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          file: Dockerfile
+          platforms: linux/amd64,linux/arm64
+          push: ${{ github.event_name != 'pull_request' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          sbom: true
+          provenance: true
+
+      - name: Sign image with Cosign (keyless OIDC)
+        if: github.event_name != 'pull_request'
+        uses: sigstore/cosign-installer@v3
+      - name: Cosign sign
+        if: github.event_name != 'pull_request'
+        run: cosign sign --yes ${{ steps.vars.outputs.canonical }}@${{ steps.build.outputs.digest }}
+
+      - name: Attest image provenance
+        if: github.event_name != 'pull_request'
+        uses: actions/attest-build-provenance@v2
+        with:
+          subject-name: ${{ steps.vars.outputs.canonical }}
+          subject-digest: ${{ steps.build.outputs.digest }}
+          push-to-registry: true
+
+