Fix flaky playground e2e tests

packages/playground-website/e2e/playwright.config.ts

@@ -7,11 +7,21 @@ const root = resolve(__dirname, "..");
 
 const config: PlaywrightTestConfig = {
   forbidOnly: !!process.env.CI,
+  // Safety net for the occasional e2e flake in CI.
+  retries: process.env.CI ? 1 : 0,
   timeout: 120 * 1000,
   expect: { timeout: 10_000 },
   webServer: {
-    command: "pnpm watch",
+    // Serve the pre-built app instead of the Vite dev server (`pnpm watch`).
+    // The dev server transforms modules on demand and re-optimizes dependencies
+    // on the first page load; discovering a new dependency mid-load triggers a
+    // full page reload that aborts the in-flight `page.goto` (net::ERR_ABORTED),
+    // which intermittently failed whichever test ran first. `vite preview` serves
+    // the static build (the `test:e2e` task already depends on `build`), so there
+    // is no on-demand transform, dependency re-optimization, or HMR reload.
+    command: "vite preview --port 5173 --strictPort",
     port: 5173,
+    cwd: root,
     timeout: 120 * 1000,
     reuseExistingServer: !process.env.CI,
   },