根据提供的code differences信息，由于没有具体的代码变更内容，我将生成一个通用的commit message模板：

```
docs(readme): 更新文档说明

- 添加项目使用指南
- 完善API接口说明
- 修正错误的配置示例
```

注意：由于您提供的code differences部分为空，以上是一个示例模板。当您有具体的代码变更时，请提供详细的变更内容以便生成更准确的commit message。

Assets/Scripts/技能脚本/ShieldGuardSkill.cs

@@ -0,0 +1,62 @@
+using UnityEngine;
+
+public class ShieldGuardSkill : UnitSkill
+{
+    [Header("盾牌参数")]
+    [Min(1f)]
+    public float shieldDurability = 220f;
+
+    [Min(0.1f)]
+    public float shieldDuration = 4f;
+
+    [Range(0f, 1f)]
+    public float damageReduction = 0.35f;
+
+    public Vector3 shieldLocalPosition = new Vector3(0f, 1f, 0.7f);
+
+    public Vector3 shieldSize = new Vector3(1.5f, 1.8f, 0.12f);
+
+    private ShieldBarrier shield;
+
+    public ShieldBarrier ActiveShield => shield;
+
+    public override void ReleaseSkill()
+    {
+        EnsureShield();
+        shield.Refresh(shieldDurability, shieldDuration, shieldLocalPosition, shieldSize);
+    }
+
+    public override float ModifyIncomingDamage(float damage, GameObject attacker)
+    {
+        if (shield == null || !shield.IsActive)
+        {
+            return damage;
+        }
+
+        if (shield.TryBlock(attacker, damage))
+        {
+            return damage * (1f - damageReduction);
+        }
+
+        return damage;
+    }
+
+    private void EnsureShield()
+    {
+        if (shield != null)
+        {
+            return;
+        }
+
+        GameObject shieldObject = new GameObject("ShieldBarrier");
+        shieldObject.transform.SetParent(unit.transform, false);
+
+        BoxCollider boxCollider = shieldObject.AddComponent<BoxCollider>();
+        boxCollider.isTrigger = true;
+        boxCollider.size = shieldSize;
+
+        shield = shieldObject.AddComponent<ShieldBarrier>();
+        shield.Configure(unit, boxCollider);
+        shieldObject.SetActive(false);
+    }
+}