feat: add GitHub Actions workflow for automated npm publishing

- Automated publishing on version tags (v*)
- Includes provenance for package authenticity
- Runs tests and linting before publishing
- Uses Node.js 18 and pnpm for consistency

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

Co-Authored-By: Claude <[email protected]>

Author: efouts

.github/workflows/publish.yml

@@ -0,0 +1,41 @@
+name: Publish to npm
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      id-token: write
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '18'
+          registry-url: 'https://registry.npmjs.org'
+
+      - name: Setup pnpm
+        uses: pnpm/action-setup@v2
+        with:
+          version: latest
+
+      - name: Install dependencies
+        run: pnpm install
+
+      - name: Run tests
+        run: pnpm test
+
+      - name: Run linting
+        run: pnpm run lint
+
+      - name: Publish to npm
+        run: pnpm publish --provenance --access public
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}