Gateway destinations (#21040)

* Gateway generation

* Gateway stuff

* gatewehs

* mercenaries

* play area

* Range fixes and tweaks

* weh

* Gateway UI polish

* Lots of fixes

* Knock some items off

* Fix dungeon spawning

Realistically we should probably be using a salvage job.

* wahwah

* wehvs

* expression

* weh

* eee

* a

* a

* WEH

* frfr

* Gatwey

* Fix gateway windows

* Fix gateway windows

* a

* a

* Better layer masking

* a

* a

* Noise fixes

* a

* Fix fractal calculations

* a

* More fixes

* Fixes

* Add layers back in

* Fixes

* namespaces and ftl

* Other TODO

* Fix distance

* Cleanup

* Fix test

Content.Client/Overlays/StencilOverlaySystem.cs

@@ -0,0 +1,27 @@
+using Content.Client.Parallax;
+using Content.Client.Weather;
+using Robust.Client.GameObjects;
+using Robust.Client.Graphics;
+
+namespace Content.Client.Overlays;
+
+public sealed class StencilOverlaySystem : EntitySystem
+{
+    [Dependency] private readonly IOverlayManager _overlay = default!;
+    [Dependency] private readonly ParallaxSystem _parallax = default!;
+    [Dependency] private readonly SharedTransformSystem _transform = default!;
+    [Dependency] private readonly SpriteSystem _sprite = default!;
+    [Dependency] private readonly WeatherSystem _weather = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        _overlay.AddOverlay(new StencilOverlay(_parallax, _transform, _sprite, _weather));
+    }
+
+    public override void Shutdown()
+    {
+        base.Shutdown();
+        _overlay.RemoveOverlay<StencilOverlay>();
+    }
+}