feat(accessibility): key-nav & touch-scrolling

[Rudxain]

Describe the feature you want

Support for keyboard navigation is non-existent: the arrow keys can't be used to scroll the pack list and Tab can't focus on any widget.

Surprisingly, touchscreen scrolling works (at least on Wayland+Mutter), but only when dragging the background of the pack list (a tiny margin between list items; hard to "aim"). If UAD-ng somehow falls-back to x11, then this bug may be a limitation of xwayland input-handling.

Touchscreen clicks work perfectly fine

Acknowledgements

• [X] This issue is not a duplicate of an existing feature request.
• [X] I have chosen an appropriate title.
• [X] All requested information has been provided properly.

[Rudxain]

I tested the touchscreen on a Linux system that mainly uses libinput, more specifically Debian 13 Trixie (not yet stable)