chore(deps): add eslint-plugin-playwright and fix invalid expects

eslint.config.mjs

@@ -21,6 +21,7 @@ import path from "path";
 import { fileURLToPath } from "url";
 import stylistic from "@stylistic/eslint-plugin";
 import importRules from "eslint-plugin-import";
+import playwrightPlugin from "eslint-plugin-playwright";
 import progressPlugin from "./utils/eslint-plugin-progress/index.js";
 import { fixupConfigRules } from "@eslint/compat";
 import { FlatCompat } from "@eslint/eslintrc";
@@ -496,6 +497,21 @@ export default [
       ...noFloatingPromisesRules,
     },
   },
+  {
+    // Playwright-specific guardrails applied only to spec files.
+    // - no-wait-for-timeout: warn (93 existing hits → keep CI green while flagging tech debt)
+    // - valid-expect: error (catches missing await on expect() calls)
+    // - no-focused-test: error (blocks test.only from landing; backs up forbidOnly on CI)
+    files: ["tests/**/*.spec.ts", "tests/**/*.spec.js"],
+    plugins: {
+      playwright: playwrightPlugin,
+    },
+    rules: {
+      "playwright/no-wait-for-timeout": "warn",
+      "playwright/valid-expect": "error",
+      "playwright/no-focused-test": "error",
+    },
+  },
   ...reactBaseConfig.map((config) => ({
     ...config,
     files: reactFiles,

package.json

@@ -92,7 +92,7 @@
     "chromium-bidi": "^12.0.0",
     "colors": "1.4.0",
     "commander": "^13.0.0",
-    "concurrently": "^6.2.1",
+    "concurrently": "^9.2.1",
     "cross-env": "^7.0.3",
     "dotenv": "^16.4.5",
     "electron": "^39.8.4",
@@ -101,6 +101,7 @@
     "eslint": "^9.34.0",
     "eslint-plugin-import": "^2.32.0",
     "eslint-plugin-notice": "^1.0.0",
+    "eslint-plugin-playwright": "^2.10.1",
     "eslint-plugin-react": "^7.37.5",
     "eslint-plugin-react-hooks": "^5.2.0",
     "formidable": "^2.1.1",

tests/library/resource-timing.spec.ts

@@ -129,7 +129,7 @@ it('should work when serving from memory cache', async ({ contextFactory, server
 });
 
 function verifyTimingValue(value: number, previous: number) {
-  expect(value === -1 || value > 0 && value >= previous);
+  expect(value === -1 || value > 0 && value >= previous).toBeTruthy();
 }
 
 function verifyConnectionTimingConsistency(timing) {