Pre-Seshn Starting page

when entering the study page, currently goes straight to the timer screen. it would be nice to have another page that comes before that screen, which says something like: "Begin study Seshn".

Start at the study page entry point and trace how it currently reaches the timer screen. Add an intermediate page presenting a “Begin study Seshn” message, then verify that entering the study flow reaches this page before the timer.

Written by the indexing model from the issue text.