ci: add GitHub Actions workflow for automated testing

Add a GitHub Actions workflow that runs the test suite on push and pull requests. This ensures code quality and catches issues early in the development process.

Features:
- Runs on push to main and claude/** branches
- Runs on all pull requests to main
- Tests against Node.js 18, 20, and 22 for compatibility
- Uses npm cache for faster builds
- Executes `npm install && npm test`

The workflow will help maintain code quality and provide immediate feedback on test failures.

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

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

Author: claude

.github/workflows/test.yml

@@ -0,0 +1,34 @@
+name: Tests
+
+on:
+  push:
+    branches:
+      - main
+      - "claude/**"
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [18, 20, 22]
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          cache: 'npm'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Run tests
+        run: npm test