chore(packages): add test coverage support to plugin sdk and shared package

.github/workflows/test.yml

@@ -78,7 +78,50 @@ jobs:
         run: cd shared && npm run typecheck
 
       - name: Run tests
-        run: cd shared && npm test
+        run: cd shared && npm run test:coverage
+
+      - name: Upload coverage
+        if: success()
+        uses: actions/upload-artifact@v6
+        with:
+          name: shared-coverage
+          path: shared/coverage/
+          retention-days: 7
+
+  plugin-sdk-tests:
+    name: Plugin SDK Tests
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: plugin-sdk
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: actions/setup-node@v6
+        with:
+          # 22 matches the TREK server runtime and has node:sqlite, which the
+          # dev-server tests exercise (same choice as publish-plugin-sdk.yml).
+          node-version: 22
+
+      # plugin-sdk is standalone (own lockfile, not a root workspace), so it
+      # installs from its own directory.
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Typecheck
+        run: npm run typecheck
+
+      - name: Run tests
+        run: npm run test:coverage
+
+      - name: Upload coverage
+        if: success()
+        uses: actions/upload-artifact@v6
+        with:
+          name: plugin-sdk-coverage
+          path: plugin-sdk/coverage/
+          retention-days: 7
 
   server-tests:
     name: Server Tests