NPC refactor (#10122)

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

Content.Server/NPC/HTN/HTNPlan.cs

@@ -0,0 +1,31 @@
+using Content.Server.NPC.HTN.PrimitiveTasks;
+
+namespace Content.Server.NPC.HTN;
+
+/// <summary>
+/// The current plan for a HTN NPC.
+/// </summary>
+public sealed class HTNPlan
+{
+    /// <summary>
+    /// Effects that were applied for each primitive task in the plan.
+    /// </summary>
+    public readonly List<Dictionary<string, object>?> Effects;
+
+    public List<int> BranchTraversalRecord;
+
+    public List<HTNPrimitiveTask> Tasks;
+
+    public int Index = 0;
+
+    public HTNPrimitiveTask CurrentTask => Tasks[Index];
+
+    public HTNOperator CurrentOperator => CurrentTask.Operator;
+
+    public HTNPlan(List<HTNPrimitiveTask> tasks, List<int> branchTraversalRecord, List<Dictionary<string, object>?> effects)
+    {
+        Tasks = tasks;
+        BranchTraversalRecord = branchTraversalRecord;
+        Effects = effects;
+    }
+}