ci(release): update actions to Node 24 versions & optimize workflow

- Bump all actions off the deprecated Node 20 runtime: checkout v4->v7,
  upload-artifact v4->v7, setup-node added@v6, action-gh-release v1->v3,
  docker build-push v5->v7, login v3->v4, metadata v5->v6, buildx v3->v4
  (verified latest majors via GitHub API; no breaking input/output changes)
- Add npm dependency caching via setup-node (cache: npm)
- Add GHA layer caching for the multi-arch Docker build (cache-from/to gha)
- Add concurrency group so a release run is never interrupted, only dedupes
  re-pushes of the same tag
- Tighten release-server permissions to contents: read (it never writes to the repo)

Version-injection and commit-back logic unchanged. First exercised on the next v* tag.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -5,23 +5,29 @@ on:
     tags:
       - 'v*'
 
+# A release run must never be interrupted (it commits back to main and publishes
+# artifacts). Only dedupe accidental re-pushes of the same tag.
+concurrency:
+  group: release-${{ github.ref_name }}
+  cancel-in-progress: false
+
 jobs:
   release-server:
     runs-on: ubuntu-latest
     permissions:
-      contents: write
+      contents: read
       packages: write
       id-token: write
       attestations: write
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
 
       - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3
+        uses: docker/setup-buildx-action@v4
 
       - name: Log in to GitHub Container Registry
-        uses: docker/login-action@v3
+        uses: docker/login-action@v4
         with:
           registry: ghcr.io
           username: ${{ github.actor }}
@@ -29,7 +35,7 @@ jobs:
 
       - name: Extract Docker metadata
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@v6
         with:
           images: ghcr.io/${{ github.repository }}
           tags: |
@@ -38,7 +44,7 @@ jobs:
 
       - name: Build and push Docker image
         id: build
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v7
         with:
           context: .
           file: server/Dockerfile
@@ -46,6 +52,9 @@ jobs:
           platforms: linux/amd64,linux/arm64
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
+          # Reuse layers across releases to speed up the multi-arch build.
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
 
       - name: Generate artifact attestation
         uses: actions/attest@v4
@@ -62,7 +71,13 @@ jobs:
       attestations: write
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@v7
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: '24'
+          cache: 'npm'
 
       - name: Extract version from tag
         id: version
@@ -128,14 +143,14 @@ jobs:
         run: node website/build.cjs
 
       - name: Upload Website Artifacts
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: website-www
           path: website/www/
           if-no-files-found: error
 
       - name: Create GitHub Release
-        uses: softprops/action-gh-release@v1
+        uses: softprops/action-gh-release@v3
         with:
           files: |
             dist/koalasync-chrome.zip