[Enhancement] 📒Display number of entries in a Notepad

[AltoRetrato]

I can't find a way to see the number of entries in a notepad. The only alternative I've found is to "Export Notepad as CSV" and opening the CSV file, which is not very practical.

I think it would be useful to see the number of entries, and perhaps even some other details such as date of creation and last update, quiz statistics (total number of quizzes, number of unique items quizzed, correct guesses percentage, etc.)

Maybe a new entry "Category information" under "Merge Into Category" could open a window with that information?