style: dart format 적용

lib/src/core/model/save_data.dart

@@ -181,7 +181,10 @@ class GameSave {
             )
             .toList(),
       ),
-      equipment: _equipmentFromJson(equipmentJson, json['version'] as int? ?? 2),
+      equipment: _equipmentFromJson(
+        equipmentJson,
+        json['version'] as int? ?? 2,
+      ),
       skillBook: SkillBook(
         skills: skillsJson
             .map(
@@ -333,10 +336,7 @@ Equipment _equipmentFromJson(Map<String, dynamic> json, int version) {
       }
     }
 
-    return Equipment(
-      items: items,
-      bestIndex: json['bestIndex'] as int? ?? 0,
-    );
+    return Equipment(items: items, bestIndex: json['bestIndex'] as int? ?? 0);
   }
 
   // v2 이하: 레거시 형식 (문자열 기반)