chore: add .editorconfig and consistent formatting for backend projects

Adds an `.editorconfig` file with C# and project-specific conventions. Applies consistent indentation and formatting across backend handlers, runtime models, and AI services.

apps/backend/Universe/Simulation/SimulationHostedService.cs

@@ -2,18 +2,18 @@ namespace SpaceGame.Api.Universe.Simulation;
 
 public sealed class SimulationHostedService(WorldService worldService) : BackgroundService
 {
-  protected override async Task ExecuteAsync(CancellationToken stoppingToken)
-  {
-    using var timer = new PeriodicTimer(TimeSpan.FromMilliseconds(200));
-    try
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
-      while (!stoppingToken.IsCancellationRequested && await timer.WaitForNextTickAsync(stoppingToken))
-      {
-        worldService.Tick(0.2f);
-      }
+        using var timer = new PeriodicTimer(TimeSpan.FromMilliseconds(200));
+        try
+        {
+            while (!stoppingToken.IsCancellationRequested && await timer.WaitForNextTickAsync(stoppingToken))
+            {
+                worldService.Tick(0.2f);
+            }
+        }
+        catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
+        {
+        }
     }
-    catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
-    {
-    }
-  }
 }