feat: add comprehensive CI workflow for quality checks

- Add GitHub Actions workflow for automated testing
- Include lint, typecheck, test, and build validation
- Support Node.js 20.12.0+ with matrix strategy
- Use pnpm 10.8.1 with dependency caching
- Verify CLI binary creation in build step

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

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

.github/workflows/ci.yml

@@ -0,0 +1,53 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    name: Quality Checks
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: ['20.12.0', '22']
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10.8.1
+
+      - name: Setup Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          cache: 'pnpm'
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Run linting
+        run: pnpm lint
+
+      - name: Run type checking
+        run: pnpm typecheck
+
+      - name: Run tests
+        run: pnpm test
+
+      - name: Build project
+        run: pnpm build
+
+      - name: Verify build artifacts
+        run: |
+          if [ ! -f "dist/index.js" ]; then
+            echo "Build failed: dist/index.js not found"
+            exit 1
+          fi
+          echo "Build successful: dist/index.js created"