chore(release): initialize github releases

.github/workflows/release.yml

@@ -0,0 +1,115 @@
+name: Release
+
+on:
+  pull_request:
+    types: [closed]
+
+permissions:
+  contents: write
+
+concurrency:
+  group: release-${{ github.repository }}
+  cancel-in-progress: false
+
+jobs:
+  release:
+    if: >-
+      github.event.pull_request.merged == true &&
+      startsWith(github.event.pull_request.head.ref, 'release/v')
+    runs-on: ubuntu-latest
+    env:
+      HEAD_REF: ${{ github.event.pull_request.head.ref }}
+      DEFAULT_BRANCH: ${{ github.event.repository.default_branch }}
+    steps:
+      - name: Check out merged pull request
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+          ref: ${{ github.event.pull_request.merge_commit_sha }}
+
+      - name: Install git-cliff
+        uses: taiki-e/install-action@git-cliff
+
+      - name: Validate release branch and tag
+        id: release
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          release_pattern='^release/v[0-9]+\.[0-9]+\.[0-9]+$'
+          if [[ ! "$HEAD_REF" =~ $release_pattern ]]; then
+            printf 'Invalid release branch: %s\n' "$HEAD_REF" >&2
+            exit 1
+          fi
+
+          version="${HEAD_REF#release/}"
+          tag_reference="refs/tags/$version"
+          if git ls-remote --exit-code --refs origin "$tag_reference" \
+              >/dev/null 2>&1; then
+            printf 'Release tag already exists: %s\n' "$version" >&2
+            exit 1
+          fi
+
+          printf 'version=%s\n' "$version" >> "$GITHUB_OUTPUT"
+
+      - name: Generate and commit changelog
+        env:
+          VERSION: ${{ steps.release.outputs.version }}
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          git cliff --config cliff.toml --tag "$VERSION" \
+            --no-exec --output CHANGELOG.md
+          heading="## [${VERSION#v}]"
+          if ! grep --fixed-strings --quiet "$heading" CHANGELOG.md; then
+            printf 'Generated changelog is missing heading: %s\n' "$heading" >&2
+            exit 1
+          fi
+
+          git config user.name github-actions[bot]
+          git config user.email \
+            41898282+github-actions[bot]@users.noreply.github.com
+          if git diff --quiet -- CHANGELOG.md; then
+            exit 0
+          fi
+
+          git add CHANGELOG.md
+          git commit -m "chore(release): update changelog for $VERSION"
+          git push origin "HEAD:$DEFAULT_BRANCH"
+
+      - name: Create and push release tag
+        env:
+          VERSION: ${{ steps.release.outputs.version }}
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          git tag "$VERSION"
+          git push origin "refs/tags/$VERSION"
+
+      - name: Generate release notes
+        env:
+          VERSION: ${{ steps.release.outputs.version }}
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          git cliff --config cliff.toml --latest --no-exec \
+            --output release-notes.md
+          if [[ ! -s release-notes.md ]]; then
+            printf 'Generated release notes are empty\n' >&2
+            exit 1
+          fi
+
+      - name: Create GitHub release
+        env:
+          GH_TOKEN: ${{ github.token }}
+          VERSION: ${{ steps.release.outputs.version }}
+        shell: bash
+        run: |
+          set -euo pipefail
+
+          gh release create "$VERSION" \
+            --title "$VERSION" \
+            --notes-file release-notes.md