Fluid spread refactor (#11908)

Co-authored-by: metalgearsloth <31366439+metalgearsloth@users.noreply.github.com>
Fix undefined

Content.Server/Fluids/ShowFluidsCommand.cs

@@ -0,0 +1,32 @@
+using Content.Server.Administration;
+using Content.Server.Fluids.EntitySystems;
+using Content.Shared.Administration;
+using Robust.Server.Player;
+using Robust.Shared.Console;
+
+namespace Content.Server.Fluids;
+
+[AdminCommand(AdminFlags.Debug)]
+public sealed class ShowFluidsCommand : IConsoleCommand
+{
+    [Dependency] private readonly IEntitySystemManager _entitySystem = default!;
+    public string Command => "showfluids";
+    public string Description => "Toggles seeing puddle debug overlay.";
+    public string Help => $"Usage: {Command}";
+    public void Execute(IConsoleShell shell, string argStr, string[] args)
+    {
+        var player = shell.Player as IPlayerSession;
+        if (player == null)
+        {
+            shell.WriteLine("You must be a player to use this command.");
+            return;
+        }
+
+        var fluidDebug = _entitySystem.GetEntitySystem<PuddleDebugDebugOverlaySystem>();
+        var enabled = fluidDebug.ToggleObserver(player);
+
+        shell.WriteLine(enabled
+            ? "Enabled the puddle debug overlay."
+            : "Disabled the puddle debug overlay.");
+    }
+}