feat: show notebook tree hierarchy in note move, tabs, and agent config

- note-card.tsx: parent/child notebook dropdown with indentation
- notes-tabs-view.tsx: tree-structured notebook picker with check marks
- agent-detail-view.tsx: source/target notebook selects with optgroup tree
- Add notebook-tree-select.tsx shared utility component

memento-note/components/note-card.tsx

@@ -504,18 +504,27 @@ export const NoteCard = memo(function NoteCard({
               <StickyNote className="h-4 w-4 mr-2" />
               {t('notebookSuggestion.generalNotes')}
             </DropdownMenuItem>
-            {notebooks.map((notebook: any) => {
-              const NotebookIcon = getNotebookIcon(notebook.icon || 'folder')
-              return (
-                <DropdownMenuItem
-                  key={notebook.id}
-                  onClick={() => handleMoveToNotebook(notebook.id)}
-                >
-                  <NotebookIcon className="h-4 w-4 mr-2" />
-                  {notebook.name}
-                </DropdownMenuItem>
-              )
-            })}
+            {notebooks.filter(nb => !nb.parentId).map((notebook: any) => {
+               const NotebookIcon = getNotebookIcon(notebook.icon || 'folder')
+               const children = notebooks.filter((c: any) => c.parentId === notebook.id)
+               return (
+                 <div key={notebook.id}>
+                   <DropdownMenuItem onClick={() => handleMoveToNotebook(notebook.id)}>
+                     <NotebookIcon className="h-4 w-4 mr-2" />
+                     {notebook.name}
+                   </DropdownMenuItem>
+                   {children.map((child: any) => {
+                     const ChildIcon = getNotebookIcon(child.icon || 'folder')
+                     return (
+                       <DropdownMenuItem key={child.id} onClick={() => handleMoveToNotebook(child.id)} className="pl-8">
+                         <ChildIcon className="h-4 w-4 mr-2" />
+                         └ {child.name}
+                       </DropdownMenuItem>
+                     )
+                   })}
+                 </div>
+               )
+             })}
           </DropdownMenuContent>
         </DropdownMenu>
       </div>}