feat: adding multi-select boxes, allowing batch deletion

[giannatan]

ref: #6

[kyrieb-ekat]

Hi! Overall looks good, but here's a couple of things that need fixing (and followed by a couple of thoughts/suggestions you can keep/toss at your discretion).
Needs:

• Esc needs to work! No Escape key handler to cancel an in-progress marquee: cancelDrawing and cancelDrag are both wired in useKeyboardShortcuts, but there's no cancelMarquee; a user mid-drag has no escape hatch if they need to abort

Thoughts:

• setSelected is kept as a wrapper around setSelectedIds, which is reasonable for backward compatibility, but its remaining call site in AnnotationList.tsx could just be migrated to setSelectedIds([id]) to retire the dual API entirely
• onPointerMove returns early when marquee is active, which silently blocks pan/drag updates. This is correct behavior, but worth a one-line comment since it's a non-obvious short-circuit that downstream something might get tripped up by
• rectsIntersect in geometry.ts is a solid AABB test but very dense on one line. Named intermediates (aRight, bRight, etc.) or a short comment would help readability

[giannatan]

Hi, thanks for the notes!! I added the 'escape' option for mid-drawing a marquee, as well as the small comments + constant naming for the rectsIntersect function. For the setSelected note, I'll look a bit more into what you suggested (since it does make sense) and probably push a commit later after I address some other features, if that's ok!