ci: build multi-arch image on native runners (no QEMU)

.github/workflows/release.yml

@@ -149,9 +149,20 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
-  docker:
-    name: Build and Push Docker Image
-    runs-on: ubuntu-latest
+  # Build each architecture natively (no QEMU emulation — emulating a Rust
+  # release compile is extremely slow) and push by digest. The merge job then
+  # assembles the multi-arch manifest from the per-arch digests.
+  docker-build:
+    name: Build Docker Image (${{ matrix.platform }})
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - platform: linux/amd64
+            runner: ubuntu-latest
+          - platform: linux/arm64
+            runner: ubuntu-24.04-arm
+    runs-on: ${{ matrix.runner }}
     permissions:
       contents: read
       packages: write
@@ -161,9 +172,6 @@ jobs:
         with:
           ref: ${{ github.event.release.tag_name }}
 
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130 # v3
-
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3
 
@@ -174,25 +182,80 @@ jobs:
           username: ${{ github.actor }}
           password: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Extract image metadata
+      - name: Image labels
         id: meta
         uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051 # v5
         with:
           images: ghcr.io/${{ github.repository }}
-          tags: |
-            type=semver,pattern={{version}},value=${{ github.event.release.tag_name }}
-            type=semver,pattern={{major}}.{{minor}},value=${{ github.event.release.tag_name }}
-            type=raw,value=latest
 
-      - name: Build and push image
+      - name: Build and push by digest
+        id: build
         uses: docker/build-push-action@10e90e3645eae34f1e60eeb005ba3a3d33f178e8 # v6
         with:
           context: .
-          platforms: linux/amd64,linux/arm64
-          push: true
-          tags: ${{ steps.meta.outputs.tags }}
+          platforms: ${{ matrix.platform }}
           labels: ${{ steps.meta.outputs.labels }}
           build-args: |
             FEATURES=sqlite,postgresql
-          cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-from: type=gha,scope=${{ matrix.platform }}
+          cache-to: type=gha,mode=max,scope=${{ matrix.platform }}
+          outputs: type=image,name=ghcr.io/${{ github.repository }},push-by-digest=true,name-canonical=true,push=true
+
+      - name: Export digest
+        run: |
+          mkdir -p "${{ runner.temp }}/digests"
+          digest="${{ steps.build.outputs.digest }}"
+          touch "${{ runner.temp }}/digests/${digest#sha256:}"
+
+      - name: Upload digest
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
+        with:
+          name: digest-${{ matrix.platform == 'linux/amd64' && 'amd64' || 'arm64' }}
+          path: ${{ runner.temp }}/digests/*
+          if-no-files-found: error
+          retention-days: 1
+
+  docker-merge:
+    name: Merge Docker Manifest
+    needs: docker-build
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    steps:
+      - name: Download digests
+        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4
+        with:
+          path: ${{ runner.temp }}/digests
+          pattern: digest-*
+          merge-multiple: true
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@8d2750c68a42422c14e847fe6c8ac0403b4cbd6f # v3
+
+      - name: Log in to GitHub Container Registry
+        uses: docker/login-action@c94ce9fb468520275223c153574b00df6fe4bcc9 # v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Image tags
+        id: meta
+        uses: docker/metadata-action@c299e40c65443455700f0fdfc63efafe5b349051 # v5
+        with:
+          images: ghcr.io/${{ github.repository }}
+          tags: |
+            type=semver,pattern={{version}},value=${{ github.event.release.tag_name }}
+            type=semver,pattern={{major}}.{{minor}},value=${{ github.event.release.tag_name }}
+            type=raw,value=latest
+
+      - name: Create and push manifest list
+        working-directory: ${{ runner.temp }}/digests
+        run: |
+          docker buildx imagetools create \
+            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
+            $(printf 'ghcr.io/${{ github.repository }}@sha256:%s ' *)
+
+      - name: Inspect image
+        run: docker buildx imagetools inspect ghcr.io/${{ github.repository }}:${{ steps.meta.outputs.version }}