As a Sales Rep or Manager
I want to only see Sales Areas assigned to me in dropdowns
So that I do not select or interact with Sales Areas I am not authorized to access.
Acceptance Criteria
- Access Control: The `SalesAreas` entity READ operation filters results based on `UserSalesAreaAccess` for the current user.
- Admin Override: `SEP_Admin` users are also subject to this check.
- Assignments: A new `AllSalesAreas` service entity is available (unrestricted) for use in the User Configuration screen to allow assigning new Sales Areas.
- Caching: User access lists are cached in-memory to minimize DB hits.
- Empty State: If a user has no assigned Sales Areas, the list is empty (and/or error).
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