Admin: Region, Market And Read-Only Admin Roles

Environment: Dev & QA
Admin access was effectively all-or-nothing, and the regions people could be assigned to were names attached to nothing — a regional role resolved to no stores, no market and no rights.

• Regions now resolve to real stores. The mapping already existed in the store roster and matches one-to-one across it, so regions are connected to it rather than guessed at.
• A regional super admin is held to their regions instead of reaching everything.
• A read-only role can see the admin without being able to change anything.
• One canonical country list. Every screen used to work out its own list of countries, so the answer to which countries you could provision into differed depending on where you asked. There is now a single list behind all of them, and both import paths check against it.