Documents the demo-productization work from this branch: the Northstar
Mobility fictional concept and scope, the five named scenarios and their
fixed records, the seed/date-anchoring strategy (including the real bug
it fixed), the in-app Demo Guide's design and the English-suggested-
questions decision, and an operational runbook covering 5/10-minute demo
flows, reset, Unraid redeploy and rollback. Updates README with current
test counts and pointers to the new docs.
