Add Vitest coverage for the Pi plugin (#2)

* Add Vitest coverage for the Pi plugin
* Add PR test workflow

Author: benvinegar

.github/workflows/test.yml

@@ -0,0 +1,28 @@
+name: Test
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out repository
+        uses: actions/checkout@v4
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run test coverage
+        run: npm run test:coverage
+
+      - name: Run type check
+        run: npm exec -- tsc --noEmit

.gitignore

@@ -1,2 +1,3 @@
 node_modules/
+coverage/
 .DS_Store