feat: MVP-5 Sprint 1 - Backup/Restore system

- Add backup types and RecallBackup format
- Create backup snapshot engine (createBackupSnapshot)
- Add IndexedDB storage for local backups
- Implement retention policy (max 10, 30-day cleanup)
- Add backup validation and restore logic (merge/replace modes)
- Add backup restore UI dialog with preview and confirmation
- Add unsaved changes guard hook
- Integrate backups section in Settings
- Add backup endpoint to export-import API

src/components/version-history.tsx

@@ -81,11 +81,11 @@ export function VersionHistory({ noteId }: VersionHistoryProps) {
 
   return (
     <Dialog open={open} onOpenChange={handleOpenChange}>
-      <DialogTrigger asChild>
-        <Button variant="outline" size="sm">
+      <div onClick={() => handleOpenChange(true)}>
+        <Button variant="outline" size="sm" className="cursor-pointer">
           <History className="h-4 w-4 mr-1" /> Historial
         </Button>
-      </DialogTrigger>
+      </div>
       <DialogContent className="max-w-2xl max-h-[80vh] overflow-hidden flex flex-col">
         <DialogHeader>
           <DialogTitle>Historial de versiones</DialogTitle>