Replace expect.js with node:assert/strict

expect.js is unmaintained and unnecessary — Node's built-in assert
module covers all our assertion patterns. This also removes expect.js
from package.json dependencies.

Made-with: Cursor

test/package-lock.json

@@ -11,7 +11,6 @@
       "dependencies": {
         "@eslint/js": "^9.37.0",
         "chromedriver": "^141.0.3",
-        "expect.js": "^0.3.1",
         "mocha": "^11.7.4",
         "selenium-webdriver": "^4.36.0",
         "superagent": "^10.2.3"
@@ -719,11 +718,6 @@
         "node": ">=0.10.0"
       }
     },
-    "node_modules/expect.js": {
-      "version": "0.3.1",
-      "resolved": "https://registry.npmjs.org/expect.js/-/expect.js-0.3.1.tgz",
-      "integrity": "sha512-okDF/FAPEul1ZFLae4hrgpIqAeapoo5TRdcg/lD0iN9S3GWrBFIJwNezGH1DMtIz+RxU4RrFmMq7WUUvDg3J6A=="
-    },
     "node_modules/extract-zip": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/extract-zip/-/extract-zip-2.0.1.tgz",