- Finished most of LuaCsSetup top-level functionality.

- Removed some unneeded interface definitions.
- Clean-slated some Services that need to be re-written.

Barotrauma/BarotraumaServer/ServerSource/LuaCs/LuaCsSetup.cs

@@ -0,0 +1,22 @@
+using Barotrauma.Networking;
+
+namespace Barotrauma;
+
+partial class LuaCsSetup
+{
+    /// <summary>
+    /// Handles changes in game states tracked by screen changes.
+    /// </summary>
+    /// <param name="screen">The new game screen.</param>
+    public partial void OnScreenSelected(Screen screen)
+    {
+        // the server is always in the running state unless explicitly stopped.
+        if (screen == UnimplementedScreen.Instance)
+            SetRunState(RunState.Unloaded);
+        SetRunState(RunState.Running);
+    }
+
+    private partial bool ShouldRunCs() => IsCsEnabled.Value || 
+                                          (GetPackage(new SteamWorkshopId(CsForBarotraumaSteamId.Value), false, false) is { } 
+                                          && GameMain.Server.ServerPeer is LidgrenServerPeer);
+}