Rebrand project: DocumentOperator to DocumentService

This commit implements a complete rebranding of the project:
- Updated all namespaces from `DocumentOperator` to `DocumentService`.
- Renamed file paths, embedded resources, and test data references.
- Updated configuration keys, logging paths, and Redis instance names.
- Revised documentation to reflect the new project name.
- Modified project and solution files to align with the new structure.
- Updated class names, DTOs, commands, queries, and handlers.
- Adjusted middleware, controllers, and API endpoints.
- Updated Swagger metadata and API titles to `DocumentService API`.
- Refactored test namespaces, resource paths, and embedded resources.
- Updated build and deployment configurations for the new name.
- Replaced all references to `DocumentOperator` in comments and literals.

These changes ensure consistency across the codebase and documentation.

DocumentOperator.Infrastructure/Configuration/ApiKeySettings.cs

@@ -1,4 +1,4 @@
-namespace DocumentOperator.Infrastructure.Configuration;
+namespace DocumentService.Infrastructure.Configuration;
 
 public class ApiKeySettings
 {

DocumentOperator.Infrastructure/Configuration/DocumentServiceSettings.cs

@@ -1,8 +1,8 @@
-namespace DocumentOperator.Infrastructure.Configuration;
+namespace DocumentService.Infrastructure.Configuration;
 
-public class DocumentOperatorSettings
+public class DocumentServiceSettings
 {
-    public const string SectionName = "DocumentOperatorSettings";
+    public const string SectionName = "DocumentServiceSettings";
 
     public string TempFolderPath { get; set; } = string.Empty;
     public int TempFileRetentionHours { get; set; }

DocumentOperator.Infrastructure/Configuration/RedisSettings.cs

@@ -1,10 +1,10 @@
-namespace DocumentOperator.Infrastructure.Configuration;
+namespace DocumentService.Infrastructure.Configuration;
 
 public class RedisSettings
 {
     public const string SectionName = "RedisSettings";
 
     public string ConnectionString { get; set; } = "localhost:6379";
-    public string InstanceName { get; set; } = "DocumentOperator:";
+    public string InstanceName { get; set; } = "DocumentService:";
     public int CacheExpirationMinutes { get; set; } = 60;
 }

DocumentOperator.Infrastructure/Configuration/TenantInfo.cs

@@ -1,4 +1,4 @@
-namespace DocumentOperator.Infrastructure.Configuration;
+namespace DocumentService.Infrastructure.Configuration;
 
 public class TenantInfo
 {