patrickloeber/fitness-app-python-harperdb ? reverse-engineered prompt

Build me a simple workout tracker in Python that lets me save my favorite workouts, view them, update them, and delete them. I want the data stored in HarperDB, and I’d like it to feel like a small real app rather than a script, with a clean way to manage workouts from the backend.

If it makes sense, include a little helper for grabbing workout video info from YouTube so each workout can have a demo link or thumbnail. Keep the app easy to run locally, and make the main entry point clear. Use the existing files as a guide, and if you need to check current HarperDB or Python docs online, go ahead. Please wire everything together so I can start it and immediately test adding and browsing workouts.