feat(ai): 新增 IBossControl facet——Boss 阶段状态经 IAiContext 供图读取

非 Boss 敌人访问 IAiContext.Boss 显式抛 InvalidOperationException，
不返回空对象掩盖小怪图误挂 Boss 边的错误。BossResource 补 IsFull 供图条件边判定。

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Assets/_Game/Scripts/Enemies/AIBrain/EnemyBrainContext.cs

@@ -1,3 +1,4 @@
+using System;
 using UnityEngine;
 using BaseGames.AI;
 
@@ -10,11 +11,16 @@ namespace BaseGames.Enemies
     public sealed class EnemyBrainContext : IAiContext, ISensor, ICombatant, IActorVitals, IEnemyActor
     {
         readonly EnemyBase _enemy;
+        readonly BossBase  _boss;
         readonly Blackboard _blackboard = new Blackboard();
         Vector2 _lastKnown;
         float _lostTimer;
 
-        public EnemyBrainContext(EnemyBase enemy) { _enemy = enemy; }
+        public EnemyBrainContext(EnemyBase enemy)
+        {
+            _enemy = enemy;
+            _boss  = enemy as BossBase;   // 非 Boss 为 null，Boss facet 访问时显式抛
+        }
 
         // ---- IAiContext ----
         public ISensor Sensor => this;
@@ -23,6 +29,14 @@ namespace BaseGames.Enemies
         public IActorVitals Vitals => this;
         public Blackboard Blackboard => _blackboard;
 
+        /// <summary>
+        /// Boss 专属决策面。非 Boss 敌人访问即抛——小怪图误挂了 Boss 边必须立刻暴露，
+        /// 不返回空对象让错误静默通过（CLAUDE.md 第 6 条）。
+        /// </summary>
+        public IBossControl Boss => _boss ?? throw new InvalidOperationException(
+            $"[EnemyBrainContext] '{_enemy.name}' 不是 Boss（未挂 BossBase 或其子类），" +
+            "但它的 AI 图访问了 IAiContext.Boss。请检查该敌人是否误用了 Boss 专属的图或图片段。");
+
         /// <summary>每帧由 EnemyAiBrain 在 Tick 之前调用，维护最后已知位置与丢失计时（供需要的敌人用）。</summary>
         public void Refresh(float dt)
         {