AI Reachable system (#1342)

Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>

Content.Server/GameObjects/EntitySystems/AI/Pathfinding/PathfindingSystem.cs

@@ -178,6 +178,17 @@ namespace Content.Server.GameObjects.EntitySystems.AI.Pathfinding
             return newChunk;
         }
 
+        /// <summary>
+        /// Get the entity's tile position, then get the corresponding node
+        /// </summary>
+        /// <param name="entity"></param>
+        /// <returns></returns>
+        public PathfindingNode GetNode(IEntity entity)
+        {
+            var tile = _mapManager.GetGrid(entity.Transform.GridID).GetTileRef(entity.Transform.GridPosition);
+            return GetNode(tile);
+        }
+
         /// <summary>
         /// Return the corresponding PathfindingNode for this tile
         /// </summary>