Deleting a location assigned to resources returns 500 instead of 409 Conflict

[stiliyan-v]

Description

When attempting to delete a location that is currently assigned to SCL resources, the API returns a 500 Internal Server Error instead of a meaningful client error. The delete is correctly rejected server-side, but the response does not communicate why to the caller.

Acceptance Criteria

• DELETE /api/locations/{id} on an assigned location returns 409 Conflict