try again to add test runner

Author: caged

package-lock.json

@@ -18,6 +18,7 @@
     "@sveltejs/vite-plugin-svelte": "^5.0.4",
     "@web/dev-server-esbuild": "^1.0.4",
     "@web/test-runner": "^0.20.2",
+    "@web/test-runner-puppeteer": "^0.18.0",
     "autoprefixer": "^10.4.4",
     "chai": "^6.2.1",
     "mocha": "^11.7.5",