ci: restore auto-release workflow for GitHub Releases

.github/workflows/release.yml

@@ -0,0 +1,43 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - 'v[0-9]+.[0-9]+.[0-9]+'
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Extract version from tag
+        id: version
+        run: echo "VERSION=${GITHUB_REF#refs/tags/v}" >> $GITHUB_OUTPUT
+
+      - name: Extract changelog section
+        id: changelog
+        run: |
+          VERSION="${{ steps.version.outputs.VERSION }}"
+          awk -v ver="$VERSION" '
+            /^## \[/ {
+              if (found) exit
+              if ($0 ~ "\\[" ver "\\]") found=1
+            }
+            found {print}
+          ' CHANGELOG.md > release_notes.md
+
+          if [ ! -s release_notes.md ]; then
+            echo "## v$VERSION" > release_notes.md
+            echo "" >> release_notes.md
+            echo "See [CHANGELOG.md](https://github.com/${{ github.repository }}/blob/main/CHANGELOG.md) for details." >> release_notes.md
+          fi
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          body_path: release_notes.md