feat: 무기 배율 시스템 통합

- DamageEffect: 무기 데미지 배율 적용 (GetDamageMultiplier)
- PlayerSkillInput: 무기 마나 소모 배율 적용 (GetActualManaCost)
- SkillEffect: 무기 사거리 배율 적용 (가상 메서드로 구현)

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

Assets/Scripts/Skills/SkillEffect.cs

@@ -1,5 +1,7 @@
+using System.Collections.Generic;
 using UnityEngine;
 using Colosseum;
+using Colosseum.Weapons;
 
 namespace Colosseum.Skills
 {
@@ -106,12 +108,13 @@ namespace Colosseum.Skills
         {
             Vector3 center = GetAreaCenter(caster);
             Collider[] hits = Physics.OverlapSphere(center, Mathf.Max(areaRadius, fanRadius), targetLayers);
-
+            // 같은 GameObject가 여러 콜라이더를 가질 수 있으므로 중복 제거
+            HashSet<GameObject> processedTargets = new HashSet<GameObject>();
             foreach (var hit in hits)
             {
                 if (hit.gameObject == caster) continue;
                 if (!IsCorrectTeam(caster, hit.gameObject)) continue;
-
+                if (processedTargets.Contains(hit.gameObject)) continue;
                 // 부채꼴 판정
                 if (areaShape == AreaShapeType.Fan)
                 {
@@ -119,6 +122,7 @@ namespace Colosseum.Skills
                         continue;
                 }
 
+                processedTargets.Add(hit.gameObject);
                 ApplyEffect(caster, hit.gameObject);
             }
         }