feat(api): Add UserAtomicLock middleware to request pipeline

- Added `UserAtomicLock` attribute to the `CreatePost` action in `PostController.cs`
- Registered `UserAtomicLockMiddleware` as a singleton in `Startup.cs`
- Added `app.UseMiddleware<UserAtomicLockMiddleware>()` in the HTTP request pipeline

WowsKarma.Api/Controllers/PostController.cs

@@ -196,7 +196,7 @@ public IActionResult GetLatestPosts(
 	/// <response code="422">Attached replay is invalid.</response>
 	/// <response code="403">Restrictions are in effect for one of the targeted accounts.</response>
 	/// <response code="404">One of the targeted accounts was not found.</response>
-	[HttpPost, Authorize(RequireNoPlatformBans)]
+	[HttpPost, Authorize(RequireNoPlatformBans), UserAtomicLock]
 	[ProducesResponseType(201), ProducesResponseType(400), ProducesResponseType(422), ProducesResponseType(typeof(string), 403), ProducesResponseType(typeof(string), 404)]
 	public async Task<IActionResult> CreatePost(
 		[FromForm] string postDto, 

WowsKarma.Api/Startup.cs

@@ -10,7 +10,7 @@
 using System.IdentityModel.Tokens.Jwt;
 using System.Net;
 using System.Reflection;
-using System.Text;
+using System.Text; 
 using Hangfire;
 using Hangfire.PostgreSql;
 using Hangfire.Tags.PostgreSql;
@@ -280,6 +280,8 @@ public void ConfigureServices(IServiceCollection services)
 		services.AddResiliencePolicies();
 
 		services.AddSystemd();
+
+		services.AddSingleton<UserAtomicLockMiddleware>();
 	}
 
 	// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
@@ -334,7 +336,8 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
 		app.UseAuthorization();
 
 		app.UseMiddleware<RequestLoggingMiddleware>();
-
+		app.UseMiddleware<UserAtomicLockMiddleware>();
+
 		app.UseEndpoints(endpoints =>
 		{
 			endpoints.MapDefaultControllerRoute();