3b1b/videos ? reverse-engineered prompt

Build me a Python project for making 3Blue1Brown style math videos with Manim.

I want a repo where the scenes are organized by year, with a few shared helpers and custom utilities for reusing code across videos. It should be set up so I can write and run individual scenes easily, preview them, and render them the way 3Blue1Brown does. Include the basic workflow helpers for jumping into a scene, editing a bit of code, and pasting changes into an interactive session while keeping the scene state.

Make it feel like a real production workspace for explanatory math animations, not just a toy example. Add a simple example scene or two so I can see how the structure is meant to be used. If some of the older scenes need an older version of Manim, that is fine, just keep the project organized so it is clear where the legacy stuff lives. If needed, look up the current Manim docs online before wiring things up.