Sloth's subfloor vismask adventure (#35347)

* Add a subfloor vismask

Significantly cuts down on sent entity count.

* More optimisations

* Fix command

* Fixes

* namespace cleanup

* Review

* Vismasks

* Content update

* Bandaid

* awewa

* Revert these

* reh

* Update Content.Shared/SubFloor/TrayScannerComponent.cs

---------

Co-authored-by: slarticodefast <161409025+slarticodefast@users.noreply.github.com>

Content.Client/UserInterface/Systems/Sandbox/Windows/SandboxWindow.xaml.cs

@@ -1,4 +1,5 @@
-using Robust.Client.AutoGenerated;
+using Content.Client.SubFloor;
+using Robust.Client.AutoGenerated;
 using Robust.Client.UserInterface.CustomControls;
 using Robust.Client.UserInterface.XAML;
 
@@ -7,8 +8,18 @@ namespace Content.Client.UserInterface.Systems.Sandbox.Windows;
 [GenerateTypedNameReferences]
 public sealed partial class SandboxWindow : DefaultWindow
 {
+    [Dependency] private readonly IEntityManager _entManager = null!;
+
     public SandboxWindow()
     {
         RobustXamlLoader.Load(this);
+        IoCManager.InjectDependencies(this);
+    }
+
+    protected override void Opened()
+    {
+        base.Opened();
+        // Make sure state is up to date.
+        ToggleSubfloorButton.Pressed = _entManager.System<SubFloorHideSystem>().ShowAll;
     }
 }