Enhancement: Add Scroll-to-Top Shortcut

### Your use case

#### What would you like to do?

I would like to see a scroll-to-top shortcut added to the client.

#### Why would you like to do it?

Currently, scrolling back to the top of a list, whether it be a list of rooms, spaces, or similar items, is rather tedious, especially when the list contains many entries. Introducing a shortcut to return to the top of such lists would greatly enhance the user experience by offering a quick and convenient way to navigate through lengthy lists.

#### How would you like to achieve it?

I've presented some ideas on how such functionality could be implemented in the parent [discussion](https://github.com/element-hq/element-meta/discussions/2991).

### Have you considered any alternatives?

In regard to alternative ways to implement such functionality, see the parent [discussion](https://github.com/element-hq/element-meta/discussions/2991).

### Additional context

_No response_

### Are you willing to provide a PR?

No

No source files, tests, or entry points are named in the issue. Start by reading the linked parent discussion to understand the proposed shortcut behavior and affected list types; done means the agreed scroll-to-top shortcut works for the relevant client lists.

Written by the indexing model from the issue text.