making the landing page for both authenticated and unauthenticated users

Task is to make the basic landing page for all users at first.

But, after successfull registration or sign-in, the authenticated user shall see a more personalised landing page, like displaying the profile name, a dedicated profile page and many more.

No files or tests are named. Start by locating the landing page and the registration/sign-in flow, then determine how authenticated and unauthenticated users are distinguished. Done means all users see a basic landing page, while signed-in users see a personalized page with their profile name and a dedicated profile page.

Written by the indexing model from the issue text.