Fix having to click logout twice

[yxli001]

NOTE

The original issue was happening because the tabs layout isn't redirecting away when the state of firebaseUser changes. I think the second click to logout throws an error since the user is already logged out and forces the app to refresh, then the root index.ts gets rendered and redirects the app to the login layout.

Changes

• Made tabs layout redirect to login when the user is not logged in
• Removed index.ts from root layout since it was doing the redirecting before, but things don't redirect correctly when it's in the tabs layout since the index page isn't being rendered anymore
• Removed the home route and just put everything in the root app directory
  • the routes under (auth) don't conflict with (tabs) so I felt like this was cleaner
  • The app renders index.ts under (tabs) on start up

Unrelated changes

• Updated auth.ts to use react-native-firebase's modular SDK since it was giving warnings
  • This somehow caused eslint to hang on this file. ChatGPT said it was because of how react-native-firebase is structure internally so there's nothing we can do. I just added auth.ts to .eslintignore so it doesn't hang and actually lets me commit.

Testing

• Manual testing