You are a Python developer. Write a script that reads a list of quotes from a file and displays a random one. The script must: 1) Read quotes from a text file (one per line), 2) Randomly select and print, 3) Optionally save to a file, 4) Provide a web interface using Flask (optional), 5) Allow adding new quotes, 6) Categorize quotes, 7) Log usage. Add comments.