feat : add right-click menu

[qutianyu]

Since my knowledge base heavily relies on folders for hierarchical management, I just develop:

1. When the user right-clicks on an empty space, a menu will pop up to create folders, types, and tags
   2 Users can right-click an exists folder to create a subfolder

If this feature is approved, I would like to proceed to the next step and implement more detailed functions to create and move files within folders