backend phase 4: geography, addresses & nurse service areas

Adds the province -> city -> district reference hierarchy (geo schema,
seeded with 31 provinces + capital cities + Tehran's 22 districts),
nurse service areas (district_id NULL = whole city, filtered-index-pair
uniqueness -> 409), and encrypted, geocoded customer addresses with a
single-primary invariant. Introduces the IGeocoder seam (mocked) and
409 Conflict on the result envelope. Public cascading lookups are cached
behind a generation-token scheme with invalidate-on-admin-write.

One EF migration (GeographyAddressesServiceAreas, applied). Contract +
swagger snapshot + handoff/report/registry updated. 103 tests pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

server/src/API/Baya.WebFramework/BaseController/BaseController.cs

@@ -46,6 +46,10 @@ public class BaseController : ControllerBase
             return new JsonResult(new ApiResult(false, ApiResultStatusCode.Forbidden, FirstErrorMessage(result)))
                 { StatusCode = StatusCodes.Status403Forbidden };
 
+        if (result.IsConflict)
+            return new JsonResult(new ApiResult(false, ApiResultStatusCode.Conflict, FirstErrorMessage(result)))
+                { StatusCode = StatusCodes.Status409Conflict };
+
         AddErrors(result);
         
         var badRequestErrors = new ValidationProblemDetails(ModelState);