refactor (v2): better arch

Co-authored-by: Copilot <copilot@github.com>

k-notes-frontend/src/components/note-card.tsx

@@ -165,14 +165,14 @@ export function NoteCard({ note }: NoteCardProps) {
       </Card>
 
       <Dialog open={editing} onOpenChange={setEditing}>
-        <DialogContent className="max-w-3xl max-h-[85vh] flex flex-col p-6 gap-0 overflow-hidden">
+        <DialogContent className="max-w-3xl max-h-[85dvh] flex flex-col p-6 gap-0 overflow-hidden">
           <DialogHeader className="pb-4 shrink-0">
             <DialogTitle>{t("Edit Note")}</DialogTitle>
           </DialogHeader>
           <div className="flex-1 min-h-0 overflow-y-auto -mx-6 px-6">
             <NoteForm
               defaultValues={{
-                title: note.title,
+                title: note.title ?? undefined,
                 content: note.content,
                 is_pinned: note.is_pinned,
                 color: note.color,
@@ -189,7 +189,7 @@ export function NoteCard({ note }: NoteCardProps) {
         open={historyOpen}
         onOpenChange={setHistoryOpen}
         noteId={note.id}
-        noteTitle={note.title}
+        noteTitle={note.title ?? ""}
       />
 
       <NoteViewDialog