```

feat(EliteSoldier): 精锐士兵重构为刺客定位技能体系

- 完全重写EliteSoldierSkill.cs，将职业定位从大剑狂战改为刺客
- 实现1级【裂空突袭】：飞天斩击敌方后排，造成200%物理暴击伤害
- 添加3级【弱点锁定】：伤害提升至250%，暴击率+25%，落地移速+35%
- 添加6级【影袭破防】：目标眩晕1.2秒且物理易伤35%
- 添加10级【死斗连环】：击杀后连斩最多3次，无缝腾空攻击下一个后排
- 优化动画系统：飞跃期间关闭root motion和nav mesh agent避免位移冲突
- 更新动画控制器override controller的clip引用
- 在预制体中添加isStunImmune字段用于10级霸体效果
- 更新游戏说明文档中的技能描述和开发日志
```

Assets/Scripts/技能脚本/CastleMageSkill.cs

@@ -83,16 +83,82 @@ public class CastleMageSkill : UnitSkill
         Debug.Log($"<color=orange>【爆裂火球】发射！</color> 伤害倍率: {damageMultiplier * 100:F0}%, 范围: {radius:F1}m (等级: {level})");
     }
 
-    private IEnumerator LaunchSecondFireballDelayed(GameObject target, float damageMultiplier, float radius, bool createBurnField)
+    private IEnumerator LaunchSecondFireballDelayed(GameObject primaryTarget, float damageMultiplier, float radius, bool createBurnField)
     {
         yield return new WaitForSeconds(0.25f);
-        if (target != null && target.activeInHierarchy && unit != null)
+        if (unit == null) yield break;
+
+        // 优先打目标后方的敌人；如果只有一个怪或没有更后方的人，直接打同一个目标，绝不打空
+        GameObject secondTarget = FindBacklineTarget(primaryTarget);
+
+        if (secondTarget != null && secondTarget.activeInHierarchy)
         {
-            LaunchFireball(target, damageMultiplier, radius, createBurnField);
-            Debug.Log($"<color=red>【双发爆裂】追加第二发火球！</color> 伤害倍率: {damageMultiplier * 100:F0}%");
+            LaunchFireball(secondTarget, damageMultiplier, radius, createBurnField);
+            bool isSameTarget = secondTarget == primaryTarget;
+            Debug.Log($"<color=red>【双发爆裂】追加第二发火球！</color> 目标: {secondTarget.name} ({(isSameTarget ? "单目标连续轰炸" : "后排敌群轰炸")})，伤害倍率: {damageMultiplier * 100:F0}%");
         }
     }
 
+    /// <summary>
+    /// 寻找位于当前目标后方的敌人。若无后排敌人，回退返回当前目标。
+    /// </summary>
+    private GameObject FindBacklineTarget(GameObject currentTarget)
+    {
+        if (unit == null) return currentTarget;
+
+        UnitTeam myTeam = unit.GetComponent<UnitTeam>();
+        if (myTeam == null) return currentTarget;
+
+        // 如果原目标已失效/死亡，回退找任意当前有效目标
+        if (currentTarget == null || !currentTarget.activeInHierarchy)
+        {
+            return unit.FindNearestEnemyForSkill();
+        }
+
+        Vector3 magePos = unit.transform.position;
+        Vector3 targetPos = currentTarget.transform.position;
+        Vector3 forwardDir = (targetPos - magePos).normalized;
+        if (forwardDir.sqrMagnitude < 0.001f) forwardDir = unit.transform.forward;
+
+        var allTeams = Object.FindObjectsOfType<UnitTeam>();
+        GameObject bestBacklineTarget = null;
+        float bestDistance = float.MaxValue;
+
+        foreach (var t in allTeams)
+        {
+            if (t == null || !t.gameObject.activeInHierarchy) continue;
+            if (!myTeam.IsEnemy(t.gameObject)) continue;
+            if (t.gameObject == currentTarget || t.transform.root == currentTarget.transform.root) continue;
+
+            // 检查敌方单位是否存活
+            var targetUnit = t.GetComponentInParent<UnitBase>();
+            if (targetUnit != null && targetUnit.IsDead) continue;
+            var bar = t.GetComponentInParent<WorldHealthBar>();
+            if (bar != null && bar.IsDead) continue;
+
+            GameObject enemyGo = targetUnit != null ? targetUnit.gameObject : t.gameObject;
+
+            // 计算该敌人相对当前目标的深度 (沿法师射向的距离)
+            Vector3 offset = enemyGo.transform.position - targetPos;
+            float depth = Vector3.Dot(offset, forwardDir);
+
+            // 只要位于目标后方 (深度 > 0.8米)
+            if (depth > 0.8f)
+            {
+                // 优先选择距离当前目标最近的后排敌人（紧邻的后排敌群），形成层次分明的前后封锁
+                float dist = offset.magnitude;
+                if (dist < bestDistance)
+                {
+                    bestDistance = dist;
+                    bestBacklineTarget = enemyGo;
+                }
+            }
+        }
+
+        // 如果找到了后排敌人，打后排敌人；如果场上只有一个怪或无后排敌人，打同一个目标
+        return bestBacklineTarget != null ? bestBacklineTarget : currentTarget;
+    }
+
     private void LaunchFireball(GameObject target, float damageMultiplier, float radius, bool createBurnField)
     {
         GameObject missilePrefab = fireballMissilePrefab;