Hide Categories on select or 'recommended scroll'

## Description

Hide categories when some category is selected or when recommended gets scrolled on.


## Acceptance criteria

Categories should be hidden but display the current category, with the option to close/cancel.
- on cancel: scroll to top and show categories

Start by locating the category selection and recommended-scroll UI in the TypeScript code, then inspect how the current category and cancel behavior are handled. Done means categories are hidden after selection or recommended content is scrolled into view, the current category remains visible, and cancel scrolls to the top and restores the categories.

Written by the indexing model from the issue text.