fix(gro-56): guard dev login page behind import.meta.env.DEV

The DevLoginSelector page (including the "Continue as default dev user"
button) was rendering in production when AUTH_DISABLED=true. This guards
the /login route so the page only renders in Vite development mode
(import.meta.env.DEV). Also removes the skip-login button entirely since
it bypassed user selection without any identity assertion.

- Guard /login route with import.meta.env.DEV in App.tsx
- Remove skipLogin button from DevLoginSelector.tsx
- Add vite/client types to web tsconfig
- Remove corresponding e2e test

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/tsconfig.json

@@ -7,7 +7,8 @@
     "jsx": "react-jsx",
     "strict": true,
     "noUncheckedIndexedAccess": true,
-    "skipLibCheck": true
+    "skipLibCheck": true,
+    "types": ["vite/client"]
   },
   "include": ["src"]
 }