On the Base SQLite schema User.roles is a JSON string[], so no model field
references the Role enum and the generated client no longer exports it.
Importing it yields undefined; app-header's isAdmin did Role.ADMIN and took
down the whole authenticated shell with a 500. Match the role name directly
in the four value-usages (isAdmin, the admin update schema, the role
combobox, the seed). Fixes the authenticated app on 0.1.1's Base cutover.