chore: bump @playwright/test to ^1.57.0; drop unused root dotenv

The root devDependencies still pinned an older Playwright (1.48.2)
plus a stray `dotenv` that nothing in the e2e suite or root scripts
actually requires (verified via grep across tests/). Updates the
Playwright version to match the current upstream stable and removes
the unused dotenv to keep the root install lean.

Originated from a local stash that picked up these changes; landing
them as a small dedicated commit so they don't blend into the auth
fix that follows.

package.json

@@ -8,8 +8,7 @@
     "node-fetch": "^2.7.0"
   },
   "devDependencies": {
-    "@playwright/test": "^1.48.2",
-    "dotenv": "^17.3.1",
+    "@playwright/test": "^1.57.0",
     "puppeteer": "^24.17.0"
   },
   "overrides": {