Implement LLM provider configuration and update user settings

- Added functionality to update the default LLM provider for users via a new endpoint in UserController.
- Introduced LlmProvider enum to manage available LLM options: Auto, Gemini, OpenAI, and Claude.
- Updated User and UserEntity models to include DefaultLlmProvider property.
- Enhanced database context and migrations to support the new LLM provider configuration.
- Integrated LLM services into the application bootstrap for dependency injection.
- Updated TypeScript API client to include methods for managing LLM providers and chat requests.

src/Managing.Bootstrap/ApiBootstrap.cs

@@ -425,6 +425,11 @@ public static class ApiBootstrap
         // Admin services
         services.AddSingleton<IAdminConfigurationService, AdminConfigurationService>();
 
+        // LLM and MCP services
+        services.AddScoped<ILlmService, Managing.Application.LLM.LlmService>();
+        services.AddScoped<IMcpService, Managing.Application.LLM.McpService>();
+        services.AddScoped<Managing.Mcp.Tools.BacktestTools>();
+
         return services;
     }