Configure Node.js v20 for local development

- Add .node-version and .nvmrc files specifying Node 20.9.0
- Add engines field to package.json requiring Node 20
- Re-enable dist build/check hooks in pre-commit
- Add build-dist workflow for automated builds with Node 20
- Update documentation with Node version requirements

This ensures consistent builds between local development and CI.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.github/workflows/build-dist.yml

@@ -0,0 +1,52 @@
+name: Build dist
+
+on:
+  push:
+    branches: [main]
+    paths:
+      - 'index.js'
+      - 'lib/**'
+      - 'package.json'
+      - 'package-lock.json'
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Build dist
+        run: npm run build
+
+      - name: Check for changes
+        id: check-changes
+        run: |
+          if [ -n "$(git status --porcelain dist)" ]; then
+            echo "changes=true" >> $GITHUB_OUTPUT
+          else
+            echo "changes=false" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Commit and push if changed
+        if: steps.check-changes.outputs.changes == 'true'
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+          git add dist/
+          git commit -m "Build dist with Node 20
+
+          🤖 Automated build from workflow"
+          git push

.node-version

@@ -0,0 +1 @@
+20.9.0

.nvmrc

@@ -0,0 +1 @@
+20.9.0

.pre-commit-config.yaml

@@ -28,18 +28,17 @@ repos:
         args: ['--fix']
         exclude: ^dist/
 
-  # Disabled local hooks because dist/ formatting can vary between Node versions
-  # - repo: local
-  #   hooks:
-  #     - id: build-dist
-  #       name: Build dist
-  #       entry: npm run build
-  #       language: system
-  #       pass_filenames: false
-  #       files: ^(index\.js|lib/.*\.js)$
-  #     - id: check-dist
-  #       name: Check dist is up to date
-  #       entry: bash -c 'if [ -n "$(git status --porcelain dist)" ]; then echo "dist is out of date. Run npm run build and commit the changes."; exit 1; fi'
-  #       language: system
-  #       pass_filenames: false
-  #       always_run: true
+  - repo: local
+    hooks:
+      - id: build-dist
+        name: Build dist
+        entry: npm run build
+        language: system
+        pass_filenames: false
+        files: ^(index\.js|lib/.*\.js)$
+      - id: check-dist
+        name: Check dist is up to date
+        entry: bash -c 'if [ -n "$(git status --porcelain dist)" ]; then echo "dist is out of date. Run npm run build and commit the changes."; exit 1; fi'
+        language: system
+        pass_filenames: false
+        always_run: true

CLAUDE.md

@@ -84,14 +84,14 @@ Each test case has `old/` and `new/` subdirectories with Go code.
 
 The action uses `@vercel/ncc` to compile all dependencies into a single `dist/index.js` file. This is required for GitHub Actions and must be committed to the repository. The dist/ folder is intentionally NOT in .gitignore.
 
-**Important**: Build with Node.js v20 to ensure consistent output with CI.
+**Important**: The dist must be built with Node.js v20 to match GitHub Actions runtime.
 
-To update dist/ after making changes:
+There are two ways to update dist/:
 
+1. **Automatic (recommended)**: Push changes to main branch and the build-dist workflow will automatically rebuild with Node 20
+2. **Manual**: If you have Node 20 installed locally:
    ```bash
-# Ensure you're using Node v20
-node --version  # Should show v20.x.x
-
+   node --version  # Must show v20.x.x
    npm run build
    git add dist/index.js
    ```

package.json

@@ -16,6 +16,9 @@
     "lint-staged": "^16.1.2",
     "prettier": "^3.1.1"
   },
+  "engines": {
+    "node": ">=20.0.0 <21.0.0"
+  },
   "jest": {
     "collectCoverage": true,
     "coverageThreshold": {