Add support for time limited sessions
Some ideas:
- Limit computer time per day and per week
- Allow parent to extend child’s computer time on one-off bases
- Allow that through one-time codes on bits of paper so parent doesn’t have to be present
- Gracefully handle “time’s up” by locking session, then killing it after 30 minutes (or so); reduces friction between parent and child
- Eventually save child’s session to disk to eliminate friction