Chore: prettier formatting in CI

.github/workflows/prettier.yml

@@ -0,0 +1,72 @@
+name: Prettier
+
+on:
+  pull_request:
+permissions:
+  contents: write
+jobs:
+  prettier:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v7
+        with:
+          fetch-depth: 1
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v7
+        with:
+          node-version: 24
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Get changed files and run Prettier
+        id: run_prettier
+        run: |
+          # Fetch only the base branch tip and compare it with the checked-out PR merge commit
+          git fetch --no-tags --depth=1 origin \
+            "+refs/heads/${{ github.base_ref }}:refs/remotes/origin/${{ github.base_ref }}"
+          changed_files=$(git diff --name-only --diff-filter=ACMRT origin/${{ github.base_ref }}..HEAD | grep -E '\.(js|mjs|cjs|json|css|html|md|yml)$' || true)
+
+          if [[ -n "$changed_files" ]]; then
+            echo "Found changed files to format:"
+            echo "$changed_files"
+
+            # Run prettier on the changed files
+            echo "$changed_files" | xargs npx --no-install prettier --write
+
+            # Check if prettier actually made any changes
+            if git diff --quiet && git diff --cached --quiet; then
+              echo "No formatting changes were made by Prettier"
+              echo "prettier_changes=false" >> "$GITHUB_OUTPUT"
+            else
+              echo "Prettier made formatting changes"
+              echo "prettier_changes=true" >> "$GITHUB_OUTPUT"
+            fi
+
+            echo "prose_changes=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "No relevant files were changed in this pull request branch."
+            echo "prose_changes=false" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+
+      - name: Warn when PR is from fork
+        if: steps.run_prettier.outputs.prettier_changes == 'true' && github.event.pull_request.head.repo.fork == true
+        run: |
+          echo "::warning title=Fork PR detected::Prettier made changes, but this workflow cannot push commits to fork branches. Please run Prettier locally and push the formatting commit or allow edits from maintainers."
+          echo "### Fork PR notice" >> "$GITHUB_STEP_SUMMARY"
+          echo "Prettier found formatting changes, but auto-commit is skipped for forks. Run prettier locally or allow edits from maintainers." >> "$GITHUB_STEP_SUMMARY"
+
+      - name: Commit and push changes
+        if: steps.run_prettier.outputs.prettier_changes == 'true'
+        run: |
+          git config --global user.email "github-actions[bot]@users.noreply.github.com"
+          git config --global user.name "github-actions[bot]"
+          git add .
+          git commit -m "Chore: Format files with Prettier"
+          git push origin HEAD:${{ github.head_ref }}
+          echo "Changes committed and pushed successfully"