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/投射物和特效/Projectile.cs

@@ -0,0 +1,177 @@
+using UnityEngine;
+
+public class Projectile : MonoBehaviour
+{
+    [Header("爆炸效果（可选）")]
+    public GameObject explosionPrefab;  // 爆炸特效预制体，留空则没有爆炸效果
+
+    private GameObject target;
+    private GameObject owner;
+    private float damage;
+    private float speed;
+    private float lifetime;
+    private bool registerEnergyOnHit;
+    private bool initialized;
+    private bool hasHit;
+
+    public void Initialize(
+        GameObject targetObject,
+        float damageAmount,
+        GameObject ownerObject,
+        float moveSpeed,
+        float lifeTime,
+        bool registerEnergy = true)
+    {
+        target = targetObject;
+        damage = damageAmount;
+        owner = ownerObject;
+        speed = moveSpeed;
+        lifetime = lifeTime;
+        registerEnergyOnHit = registerEnergy;
+        initialized = true;
+        hasHit = false;
+
+        // The projectile uses its own raycast hit check. Disable the collider so
+        // it cannot be destroyed or disturbed by the owner's launch socket.
+        foreach (var collider in GetComponentsInChildren<Collider>(true))
+        {
+            collider.enabled = false;
+        }
+
+        if (lifetime > 0f)
+        {
+            Destroy(gameObject, lifetime);
+        }
+    }
+
+    private void Update()
+    {
+        if (!initialized)
+        {
+            return;
+        }
+
+        if (target == null)
+        {
+            Destroy(gameObject);
+            return;
+        }
+
+        // 目标根节点位于脚底，只取水平差值，让箭保持当前高度平行飞行。
+        Vector3 offset = target.transform.position - transform.position;
+        offset.y = 0f;
+        if (offset.sqrMagnitude <= 0.01f)
+        {
+            HitTarget(target);
+            return;
+        }
+
+        Vector3 direction = offset.normalized;
+        float distance = speed * Time.deltaTime;
+        if (distance >= offset.magnitude)
+        {
+            HitTarget(target);
+            return;
+        }
+
+        // 投射物保持水平飞行，并让根节点前方始终指向当前目标。
+        transform.rotation = Quaternion.LookRotation(direction, Vector3.up);
+
+        if (Physics.Raycast(transform.position, direction, out RaycastHit hit, distance))
+        {
+            TryHit(hit.collider.gameObject);
+            if (hit.collider.transform.root == target.transform.root)
+            {
+                return;
+            }
+        }
+
+        // 火球保持 Prefab 固定角度，不随飞行方向旋转
+        // transform.forward = direction;
+        transform.position += direction * distance;
+    }
+
+    private void OnTriggerEnter(Collider other)
+    {
+        TryHit(other.gameObject);
+    }
+
+    private void OnCollisionEnter(Collision collision)
+    {
+        TryHit(collision.gameObject);
+    }
+
+    private void TryHit(GameObject hitObject)
+    {
+        if (!initialized || hitObject == null || target == null || IsOwner(hitObject))
+        {
+            return;
+        }
+
+        if (hitObject.transform.root == target.transform.root)
+        {
+            HitTarget(hitObject);
+        }
+    }
+
+    private void HitTarget(GameObject hitObject)
+    {
+        if (hasHit)
+        {
+            return;
+        }
+
+        UnitBase targetUnit = hitObject.GetComponentInParent<UnitBase>();
+        CrystalMineCapture crystalMine = hitObject.GetComponentInParent<CrystalMineCapture>();
+        BuildingHealth targetBuilding = hitObject.GetComponentInParent<BuildingHealth>();
+        WorldHealthBar targetHealthBar = hitObject.GetComponentInParent<WorldHealthBar>();
+        
+        if (targetUnit == null && crystalMine == null && targetBuilding == null && targetHealthBar == null)
+        {
+            return;
+        }
+
+        hasHit = true;
+        
+        if (targetUnit != null)
+        {
+            targetUnit.ReceiveDamage(damage, owner);
+        }
+        else if (crystalMine != null)
+        {
+            crystalMine.ReceiveCaptureDamage(damage, owner);
+        }
+        else if (targetBuilding != null)
+        {
+            targetBuilding.ReceiveDamage(damage, owner);
+        }
+        else if (targetHealthBar != null)
+        {
+            // 召唤师等特殊单位（有 WorldHealthBar 但没有 UnitBase）
+            targetHealthBar.TakeDamage(damage, owner);
+        }
+        
+        if (registerEnergyOnHit && owner != null)
+        {
+            UnitBase unit = owner.GetComponent<UnitBase>();
+            if (unit != null)
+            {
+                unit.RegisterAttackHit();
+            }
+        }
+
+        // 生成爆炸效果
+        if (explosionPrefab != null)
+        {
+            Instantiate(explosionPrefab, transform.position, Quaternion.identity);
+        }
+
+        Destroy(gameObject);
+    }
+
+    private bool IsOwner(GameObject hitObject)
+    {
+        return owner != null &&
+            (hitObject == owner || hitObject.transform.root == owner.transform.root);
+    }
+}