feat: User 회원등급 enum 추가

Author: MEOHIN

src/main/java/com/back/domain/user/enums/AbvLevel.java

@@ -0,0 +1,28 @@
+package com.back.domain.user.enums;
+
+public enum AbvLevel {
+    L1(1, 0, 10, "/img/grade/1.png"),
+    L2(2, 11, 25, "/img/grade/2.png"),
+    L3(3, 26, 45, "/img/grade/3.png"),
+    L4(4, 46, 65, "/img/grade/4.png"),
+    L5(5, 66, 85, "/img/grade/5.png"),
+    L6(6, 86, 100, "/img/grade/6.png");
+
+    public final int code;
+    public final int min, max;
+    public final String imagePath;
+
+    AbvLevel(int code, int min, int max, String imagePath) {
+        this.code = code;
+        this.min = min;
+        this.max = max;
+        this.imagePath = imagePath;
+    }
+
+    public static AbvLevel of(int percent) {
+        for (var lv : values()) {
+            if (percent >= lv.min && percent <= lv.max) return lv;
+        }
+        return L1; // 기본값
+    }
+}