Roles: kids see only their own practice (locked); parent sees both kids + reports + AI prompts (PIN-gated). All data on this device.
Click through the kids' apps and answer questions WITHOUT touching their real progress. Everything you do in Test Mode is saved in a separate sandbox. A yellow banner shows when it's on; Exit wipes the sandbox. When you deploy to the kids, they always start fresh (their devices have no data).
Seed fills both kids with sample mastery/streaks/badges so the dashboards look real. Clear wipes everything.