feat(domain): Rubro entity + domain exceptions (CAT-001)

src/api/SIGCM2.Api/Filters/ExceptionFilter.cs

@@ -169,6 +169,79 @@ public sealed class ExceptionFilter : IExceptionFilter
                 context.ExceptionHandled = true;
                 break;
 
+            // CAT-001: Rubro exceptions
+            case RubroNotFoundException rubroNotFoundEx:
+                context.Result = new ObjectResult(new
+                {
+                    error = "rubro_not_found",
+                    message = rubroNotFoundEx.Message
+                })
+                {
+                    StatusCode = StatusCodes.Status404NotFound
+                };
+                context.ExceptionHandled = true;
+                break;
+
+            case RubroNombreDuplicadoEnPadreException rubroDupEx:
+                context.Result = new ObjectResult(new
+                {
+                    error = "rubro_nombre_duplicado",
+                    message = rubroDupEx.Message
+                })
+                {
+                    StatusCode = StatusCodes.Status409Conflict
+                };
+                context.ExceptionHandled = true;
+                break;
+
+            case RubroTieneHijosActivosException rubroHijosEx:
+                context.Result = new ObjectResult(new
+                {
+                    error = "rubro_tiene_hijos_activos",
+                    message = rubroHijosEx.Message
+                })
+                {
+                    StatusCode = StatusCodes.Status409Conflict
+                };
+                context.ExceptionHandled = true;
+                break;
+
+            case RubroPadreInactivoException rubroPadreEx:
+                context.Result = new ObjectResult(new
+                {
+                    error = "rubro_padre_inactivo",
+                    message = rubroPadreEx.Message
+                })
+                {
+                    StatusCode = StatusCodes.Status400BadRequest
+                };
+                context.ExceptionHandled = true;
+                break;
+
+            case RubroMaxDepthExceededException rubroDepthEx:
+                context.Result = new ObjectResult(new
+                {
+                    error = "rubro_max_depth_exceeded",
+                    message = rubroDepthEx.Message
+                })
+                {
+                    StatusCode = StatusCodes.Status422UnprocessableEntity
+                };
+                context.ExceptionHandled = true;
+                break;
+
+            case RubroCycleDetectedException rubroCycleEx:
+                context.Result = new ObjectResult(new
+                {
+                    error = "rubro_cycle_detected",
+                    message = rubroCycleEx.Message
+                })
+                {
+                    StatusCode = StatusCodes.Status400BadRequest
+                };
+                context.ExceptionHandled = true;
+                break;
+
             // ADM-001: Medio exceptions
             case MedioCodigoDuplicadoException medioCodDupEx:
                 context.Result = new ObjectResult(new