Turn `category-chip`s into a split button

- https://m3.material.io/components/split-button/overview
- leading button opens the page
- trailing button opens the current popup.
- [`more_vert`](https://fonts.google.com/icons?selected=Material+Symbols+Outlined:more_vert:FILL@0;wght@400;GRAD@0;opsz@24&icon.size=24&icon.color=%23e3e3e3) icon?

This should make it easier to understand and make opening the actual page faster.

Start by locating the category-chip component and its current popup entry point, then compare the intended interaction with the linked Material split-button overview. Done means the leading button opens the category page, while the trailing button opens the current popup with an appropriate more_vert icon.

Written by the indexing model from the issue text.