feat(hero skill): add slot support for hero skill detail panel

1. 新增技能槽位参数，解决同底座技能（如普攻+触发技能）的分档定位问题
2. 新增2级/3级面板节点配置，自动隐藏无对应档位的面板
3. 重构英雄技能档位生成逻辑，支持按槽位精确查找技能配置
4. 优化技能弹窗渲染逻辑，传递槽位参数避免匹配错误分组

assets/script/game/common/config/heroSet.ts

@@ -1,4 +1,4 @@
-import { v3 } from "cc"
+import { v3 } from "cc"
 import { BoxSet, FacSet, FightSet } from "./GameSet"
 import { SkillOverrides, TGroup, SkillSet, FieldSkillSet, SkillConfig, SkillKind, FieldSkillConfig, FieldSkillType, mergeSkillParams } from "./SkillSet"
 import { BuffList, BuffConfig, ModOp } from "./BuffSet"