Add keyboard navigation

[JZimz]

Discord users with 15k+ libraries are asking for keyboard navigation - specifically being able to press letters to jump to games (like Windows Explorer) and use arrow keys to browse.

Right now you have to scroll or search manually, which is tedious for huge collections.

What to add:

1. Search hotkey (priority Add ability to scan existing ROM libraries #1)

• Press / to focus the search box
• This is the most practical way to navigate giant lists
• Use VueUse's useMagicKeys or onKeyStroke

2. Arrow key navigation

• Up/down to move between ROMs
• Needs to be state-based (track selected index in a ref) rather than DOM focus since VirtualScroller recycles elements
• Should scroll the selected item into view automatically

3. Alphabetical jump keys (nice-to-have)

• Press M to jump to first title starting with M
• Windows Explorer style
• Lower priority than search since search covers most use cases

Notes:

• VirtualScroller is already implemented, so this builds on top of that
• Search hotkey gives the most value for the least effort
• Arrow keys are trickier because of virtual scrolling but doable with state management

Discord Username: finner42