Clean up and reorganize using/import statements across the solution. Remove unnecessary DTO imports from Application and Infrastructure layers, and ensure Contracts DTOs are only referenced in API and BlazorWebApp layers. No business logic is changed; these updates improve code organization, reduce coupling, and clarify architectural separation between layers.
Separated LayoutDto from LayoutsController.cs into LayoutDto.cs and set its namespace to DbFirst.Application.Layouts for better code organization and maintainability.
Implemented user-customizable, persistent grid and band layouts for CatalogsGrid and MassDataGrid. Added backend API, database entity, and repository for storing layouts per user. Refactored grids to support dynamic band/column rendering, layout management UI, and per-user storage via localStorage and the new API. Registered all necessary services and updated data context. Enables flexible, user-specific grid experiences with saved layouts.
