fixing test runner

Author: Christian Kellner

.github/workflows/test.yml

@@ -14,13 +14,13 @@ jobs:
       - uses: actions/setup-node@v4
         with:
           node-version: '22'
-          cache: 'npm'
+          cache: 'yarn'
 
       - name: Install dependencies
-        run: npm ci
+        run: yarn install --frozen-lockfile
 
       - name: Run tests
-        run: npm test
+        run: yarn test
         env:
           NODE_ENV: test
           # Skip the 900 ms minimum response delay in CI to keep the suite fast.