feat: MVP-4 P2 - Preload notes on hover

- Add prefetchNote function in useNoteListKeyboard hook
- Prefetch note pages when navigating with arrow keys
- Add hover prefetch in NoteCard using router.prefetch
- Update KeyboardNavigableNoteList to use prefetchNote

src/components/note-card.tsx

@@ -1,6 +1,7 @@
 'use client'
 
 import Link from 'next/link'
+import { useRouter } from 'next/navigation'
 import { Note } from '@/types/note'
 import { Card, CardContent } from '@/components/ui/card'
 import { Badge } from '@/components/ui/badge'
@@ -16,12 +17,21 @@ const typeColors: Record<string, string> = {
 }
 
 export function NoteCard({ note }: { note: Note }) {
+  const router = useRouter()
   const preview = note.content.slice(0, 100) + (note.content.length > 100 ? '...' : '')
   const typeColor = typeColors[note.type] || typeColors.note
 
+  const handleMouseEnter = () => {
+    // Prefetch on hover for faster navigation
+    router.prefetch(`/notes/${note.id}`)
+  }
+
   return (
-    <Link href={`/notes/${note.id}`}>
-      <Card className="hover:shadow-md transition-shadow cursor-pointer h-full">
+    <Link href={`/notes/${note.id}`} prefetch={true}>
+      <Card
+        className="hover:shadow-md transition-shadow cursor-pointer h-full"
+        onMouseEnter={handleMouseEnter}
+      >
         <CardContent className="p-4">
           <div className="flex items-start justify-between gap-2 mb-2">
             <h3 className="font-semibold text-lg line-clamp-1">{note.title}</h3>