Add GitHub Actions workflow for publishing preview packages

.github/workflows/preview.yml

@@ -0,0 +1,40 @@
+name: Publish Preview Packages
+
+on:
+  pull_request_review:
+    types: [submitted]
+
+permissions: {}
+
+jobs:
+  check:
+    if: github.event.review.state == 'approved'
+    runs-on: ubuntu-latest
+    outputs:
+      has-permissions: ${{ steps.checkPermissions.outputs.require-result }}
+    steps:
+      - name: Check permissions
+        id: checkPermissions
+        uses: actions-cool/check-user-permission@v2
+        with:
+          require: "write"
+
+  publish:
+    needs: check
+    if: needs.check.outputs.has-permissions == 'true'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          # Check out the reviewed commit, not the latest PR head, to prevent
+          # publishing code that was pushed after approval.
+          ref: ${{ github.event.pull_request.head.sha }}
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: "20.x"
+
+      - run: npm ci
+      - run: npx vite build
+      - run: npx pkg-pr-new publish