added release workflow

.github/workflows/release.yaml

@@ -0,0 +1,66 @@
+name: Build and Publish Release
+
+on:
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: "Release tag (e.g., v1.0.0)"
+        required: true
+        type: string
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    steps:
+      # TODO: pin these with digests
+      - uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Install cosign
+        uses: sigstore/[email protected]
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/${{ github.repository }}
+          tags: |
+            type=raw,value=${{ inputs.tag }}
+            type=raw,value=latest
+
+      - name: Build and push Docker image
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          provenance: true
+          sbom: true
+
+      - name: Sign the images
+        env:
+          TAGS: ${{ steps.meta.outputs.tags }}
+        run: |
+          cosign sign --yes "${TAGS}"
+
+      - name: Generate SBOM attestation
+        env:
+          TAGS: ${{ steps.meta.outputs.tags }}
+        run: |
+          cosign attest --yes --type spdx --predicate sbom.spdx.json "${TAGS}"