This is a really interesting concept and a solid foundation!
Love the art style and the UI design, everything looks super clean! And swapping Shiori's outfits depending on the bookmarks, and the interactions changing is super inspired!
I definitely think having an indicator that time is passing would help, even if its just SFX, since its very easy to lose track when moving between rooms.
I might have missed the trigger for the 3rd ending but I've got no clue how to purchase the meal. Went and got all the coins and interacted with everything in the KFP, with both Kiara and Ina working, and with Bijou there, but nothing happened at all. Not sure if its a bug or its just really well hidden, I guess.
But it sounds like you already plan on returning after the jam, so I look forward to seeing what you add and discovering the other endings. Great work!