feat: 添加等级颜色显示，优化卡池和英雄等级UI

1.  新增getLvColor工具函数，根据等级返回对应颜色
2.  为英雄信息面板和卡牌添加等级文本颜色设置
3.  重构卡池等级节点命名和显示逻辑，修复prefab布局
4.  新增英雄自身等级显示组件到卡牌预制件

assets/resources/gui/element/card.prefab

@@ -68,19 +68,22 @@
       },
       {
         "__id__": 529
+      },
+      {
+        "__id__": 557
       }
     ],
     "_active": true,
     "_components": [
       {
-        "__id__": 557
+        "__id__": 563
       },
       {
-        "__id__": 559
+        "__id__": 565
       }
     ],
     "_prefab": {
-      "__id__": 561
+      "__id__": 567
     },
     "_lpos": {
       "__type__": "cc.Vec3",
@@ -12587,6 +12590,165 @@
     "targetOverrides": null,
     "nestedPrefabInstanceRoots": null
   },
+  {
+    "__type__": "cc.Node",
+    "_name": "lvl",
+    "_objFlags": 0,
+    "__editorExtras__": {},
+    "_parent": {
+      "__id__": 1
+    },
+    "_children": [],
+    "_active": true,
+    "_components": [
+      {
+        "__id__": 558
+      },
+      {
+        "__id__": 560
+      }
+    ],
+    "_prefab": {
+      "__id__": 562
+    },
+    "_lpos": {
+      "__type__": "cc.Vec3",
+      "x": 0,
+      "y": -43.506,
+      "z": 0
+    },
+    "_lrot": {
+      "__type__": "cc.Quat",
+      "x": 0,
+      "y": 0,
+      "z": 0,
+      "w": 1
+    },
+    "_lscale": {
+      "__type__": "cc.Vec3",
+      "x": 1,
+      "y": 1,
+      "z": 1
+    },
+    "_mobility": 0,
+    "_layer": 1073741824,
+    "_euler": {
+      "__type__": "cc.Vec3",
+      "x": 0,
+      "y": 0,
+      "z": 0
+    },
+    "_id": ""
+  },
+  {
+    "__type__": "cc.UITransform",
+    "_name": "",
+    "_objFlags": 0,
+    "__editorExtras__": {},
+    "node": {
+      "__id__": 557
+    },
+    "_enabled": true,
+    "__prefab": {
+      "__id__": 559
+    },
+    "_contentSize": {
+      "__type__": "cc.Size",
+      "width": 42.53515625,
+      "height": 54.4
+    },
+    "_anchorPoint": {
+      "__type__": "cc.Vec2",
+      "x": 0.5,
+      "y": 0.5
+    },
+    "_id": ""
+  },
+  {
+    "__type__": "cc.CompPrefabInfo",
+    "fileId": "4dqU3tFDtGbatoXWgLFpJA"
+  },
+  {
+    "__type__": "cc.Label",
+    "_name": "",
+    "_objFlags": 0,
+    "__editorExtras__": {},
+    "node": {
+      "__id__": 557
+    },
+    "_enabled": true,
+    "__prefab": {
+      "__id__": 561
+    },
+    "_customMaterial": null,
+    "_srcBlendFactor": 2,
+    "_dstBlendFactor": 4,
+    "_color": {
+      "__type__": "cc.Color",
+      "r": 255,
+      "g": 255,
+      "b": 255,
+      "a": 255
+    },
+    "_string": "Lv.1",
+    "_horizontalAlign": 1,
+    "_verticalAlign": 1,
+    "_actualFontSize": 20,
+    "_fontSize": 20,
+    "_fontFamily": "Arial",
+    "_lineHeight": 40,
+    "_overflow": 0,
+    "_enableWrapText": true,
+    "_font": null,
+    "_isSystemFontUsed": true,
+    "_spacingX": 0,
+    "_isItalic": false,
+    "_isBold": true,
+    "_isUnderline": false,
+    "_underlineHeight": 2,
+    "_cacheMode": 0,
+    "_enableOutline": true,
+    "_outlineColor": {
+      "__type__": "cc.Color",
+      "r": 0,
+      "g": 0,
+      "b": 0,
+      "a": 255
+    },
+    "_outlineWidth": 2,
+    "_enableShadow": false,
+    "_shadowColor": {
+      "__type__": "cc.Color",
+      "r": 0,
+      "g": 0,
+      "b": 0,
+      "a": 255
+    },
+    "_shadowOffset": {
+      "__type__": "cc.Vec2",
+      "x": 2,
+      "y": 2
+    },
+    "_shadowBlur": 2,
+    "_id": ""
+  },
+  {
+    "__type__": "cc.CompPrefabInfo",
+    "fileId": "eccX4h4XFHYICC7LZQu1sK"
+  },
+  {
+    "__type__": "cc.PrefabInfo",
+    "root": {
+      "__id__": 1
+    },
+    "asset": {
+      "__id__": 0
+    },
+    "fileId": "b3jvDRk1NNjL5FE2pyUByW",
+    "instance": null,
+    "targetOverrides": null,
+    "nestedPrefabInstanceRoots": null
+  },
   {
     "__type__": "cc.UITransform",
     "_name": "",
@@ -12597,7 +12759,7 @@
     },
     "_enabled": true,
     "__prefab": {
-      "__id__": 558
+      "__id__": 564
     },
     "_contentSize": {
       "__type__": "cc.Size",
@@ -12625,7 +12787,7 @@
     },
     "_enabled": true,
     "__prefab": {
-      "__id__": 560
+      "__id__": 566
     },
     "Lock": null,
     "unLock": null,
@@ -12653,9 +12815,12 @@
     "HF_node": {
       "__id__": 290
     },
-    "lv_node": {
+    "pool_lv_node": {
       "__id__": 491
     },
+    "lvl_node": {
+      "__id__": 560
+    },
     "ap_node": {
       "__id__": 529
     },