Refactor: Rename DocumentOperator to DocumentService

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.

DocumentService.API/Configuration/SwaggerSettings.cs

@@ -0,0 +1,33 @@
+namespace DocumentService.API.Configuration;
+
+/// <summary>
+/// Configuration settings for Swagger/OpenAPI documentation.
+/// </summary>
+public class SwaggerSettings
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    public const string SectionName = "SwaggerSettings";
+
+    /// <summary>
+    /// Enable Swagger UI in Production environment.
+    /// Default: true (allows production testing/debugging).
+    /// </summary>
+    public bool EnableInProduction { get; set; } = true;
+
+    /// <summary>
+    /// API title displayed in Swagger UI.
+    /// </summary>
+    public string Title { get; set; } = "DocumentService API";
+
+    /// <summary>
+    /// API version.
+    /// </summary>
+    public string Version { get; set; } = "v1";
+
+    /// <summary>
+    /// API description displayed in Swagger UI.
+    /// </summary>
+    public string Description { get; set; } = "PDF document processing service";
+}