An isolated sandbox for every learner, no setup

Twenty students, twenty isolated VS Code instances on the same container, each rooted at /data/instances/<id>/. Every student is alone in their own world: until the teacher needs to drop in.

She opens the student's instance ID on her browser. Her own VS Code, same data directory, same files saved a moment ago. She reads the broken function, edits it with a // TODO: try this instead comment, saves. The student's editor refreshes; the comment shows up on their next look.

When a student manages to break their environment past repair: wrong package version, deleted config, the kind of thing that ends a class period: the teacher restores yesterday's snapshot. The student's work from this morning is gone, but they're back to a working machine in seconds.

The classroom doesn't have a TA crisis at 9:47am. It has a snapshot.