[Feature request] Do not delete notebooks on startup if notebook not found

OS Version (操作系统): Windows and MacOS

VNote Version (Help - About VNote - Version: )(VNote版本): 2.8.2

Symptoms (表现): If a notebook is not found when vnote is started, the notebook is automatically removed.

How to Repro (如何复现): Create a notebook. Close vnote. Delete the folder with notebook. Start vnote. The "Fix Notebook" popup is shown saying it will remove the notebook if not located.

Explanation: A common use-case is to store notebooks on a USB flash drive, or in an encrypted container. It is normal behavior to open vnote when the flash drive is not connected or encrypted container is not decrypted. Currently it removes the notebook from vnote, and it needs to be manually added again every time.

Request:

Option 1: allow the option in the "Fix Notebook" window to not delete the notebook when pressing "cancel". Once the file exists again, selecting the notebook again should try to reread the original notebook location. If it still doesn't exist, show the "Fix Notebook" popup again.

Option 2 (better): don't do anything if the notebook can't be opened. Another notebook can be selected if needed. For the notebook which is not found and cannot be opened, show a warning "Fix" icon/button that can be clicked to change the location of the notebook or remove the notebook.

Thank you for this great program!

Start by reproducing the missing-notebook case on Windows or macOS and trace the startup "Fix Notebook" workflow. The change is done when an unavailable notebook remains available for later recovery, while the user can select another notebook and explicitly fix or remove the unavailable one.