Add Service collection extension

Author: imclint21

src/Initium/Controllers/BaseController.cs

@@ -35,9 +35,4 @@ public abstract class BaseController : ControllerBase
 	/// <returns>The parameter value if found; otherwise, null.</returns>
 	protected string? GetQueryParameter(string key) =>
 		HttpContext.Request.Query.TryGetValue(key, out var value) ? value.FirstOrDefault() : null;
-}
-
-// public class BaseController<TService>(TService service) : ApiController where TService : BaseService
-// {
-// 	protected readonly TService Service = service;
-// }
+}

src/Initium/Extensions/ServiceCollectionExtensions.cs

@@ -0,0 +1,42 @@
+using System.Diagnostics.CodeAnalysis;
+using System.Text.Json.Serialization;
+using Initium.Infrastructure.Results;
+using Initium.Infrastructure.Transformers;
+using Microsoft.Extensions.Hosting;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Mvc.ApplicationModels;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Initium.Extensions;
+
+[SuppressMessage("ReSharper", "UnusedMethodReturnValue.Global")]
+public static class ServiceCollectionExtensions
+{
+    /// <summary>
+    /// Registers and configures Initium framework services and conventions.
+    /// Applies API conventions, route slugification, lowercase URL enforcement,
+    /// JSON serialization customization, exception behavior for background services,
+    /// and a standardized invalid model state response.
+    /// This method is designed to augment existing MVC configurations without enforcing specific pipeline usage.
+    /// </summary>
+	public static IServiceCollection AddInitium(this IServiceCollection services)
+	{
+		services.Configure<MvcOptions>(options =>
+			options.Conventions.Add(new RouteTokenTransformerConvention(new SlugifyParameterTransformer())));
+		
+		services.Configure<RouteOptions>(options => options.LowercaseUrls = true);
+        services.Configure<HostOptions>(options => options.BackgroundServiceExceptionBehavior = BackgroundServiceExceptionBehavior.Ignore);
+		
+        services.Configure<JsonOptions>(options =>
+        {
+	        options.JsonSerializerOptions.WriteIndented = true;
+	        options.JsonSerializerOptions.Converters.Add(new JsonStringEnumConverter());
+        });
+        
+		services.PostConfigure<ApiBehaviorOptions>(behaviorOptions => 
+			behaviorOptions.InvalidModelStateResponseFactory = context => new InvalidModelStateResult(context));
+
+		return services;
+	}
+}