when typing @, show the last account we interacted with

it would be nice if when composing we could have a list of the latest accounts we interacted with when we type @ . so if we don't remember the account name, we could find it quickly.

by interaction I mostly mean text exchange. but fav and boost could be counted too.

thanks

Start by locating the composer’s @-mention suggestion entry point and inspect how account interaction data is currently available. Define which recent text exchanges, favourites, and boosts qualify, then verify that matching accounts appear when typing @ and that the ordering is useful.

Written by the indexing model from the issue text.