Enabled multi-targeting in `DocumentService.Application` to support `net462`, `net480`, and `net8.0`. Updated dependencies with framework-specific versions and added conditional configurations for compatibility.
Refactored `DocumentService.Client` by removing redundant enums and unused code. Adjusted namespaces and project references to streamline the codebase and improve maintainability.
These changes modernize the project, enhance compatibility, and align with modular design principles.
Updated project and solution files to rename and restructure
`DocumentOperator` to `DocumentService`. Modified project
references in `DocumentService.API.csproj`, `DocumentService.Application.csproj`,
and `DocumentService.Infrastructure.csproj` to reflect the new
naming convention. Updated `DocumentService.sln` to remove
old project references, add new ones, and adjust configuration
and nested project mappings accordingly. This change aligns
the project structure with the new naming convention.
