Add NPC stuck detection (#14410)

Content.Server/NPC/Components/NPCSteeringComponent.cs

@@ -2,6 +2,7 @@ using System.Threading;
 using Content.Server.NPC.Pathfinding;
 using Content.Shared.NPC;
 using Robust.Shared.Map;
+using Robust.Shared.Serialization.TypeSerializers.Implementations.Custom;
 
 namespace Content.Server.NPC.Components;
 
@@ -39,12 +40,25 @@ public sealed class NPCSteeringComponent : Component
     /// <summary>
     /// Next time we can change our steering direction.
     /// </summary>
+    [DataField("nextSteer", customTypeSerializer:typeof(TimeOffsetSerializer))]
     public TimeSpan NextSteer = TimeSpan.Zero;
 
+    [DataField("lastSteerDirection")]
     public Vector2 LastSteerDirection = Vector2.Zero;
 
     public const int SteeringFrequency = 10;
 
+    /// <summary>
+    /// Last position we considered for being stuck.
+    /// </summary>
+    [DataField("lastStuckCoordinates")]
+    public EntityCoordinates LastStuckCoordinates;
+
+    [DataField("lastStuckTime", customTypeSerializer:typeof(TimeOffsetSerializer))]
+    public TimeSpan LastStuckTime;
+
+    public const float StuckDistance = 0.5f;
+
     /// <summary>
     /// Have we currently requested a path.
     /// </summary>