feat(游戏): 新增背景音乐资源，添加播放逻辑并优化教程UI

新增主页与战斗场景的背景音乐文件及对应的导入配置
在主页和战斗任务组件中添加循环播放背景音乐的逻辑
调整四个新手教程引导预制体的文字、字体、描边与布局参数

assets/resources/gui/element/guide4.prefab

@@ -335,12 +335,12 @@
     "__prefab": {
       "__id__": 14
     },
-    "_alignFlags": 0,
+    "_alignFlags": 36,
     "_target": null,
-    "_left": 0,
-    "_right": 0,
+    "_left": 651.948,
+    "_right": 67.05200000000002,
     "_top": 0,
-    "_bottom": 0,
+    "_bottom": 50.20600000000002,
     "_horizontalCenter": 0,
     "_verticalCenter": 0,
     "_isAbsLeft": true,
@@ -349,7 +349,7 @@
     "_isAbsBottom": true,
     "_isAbsHorizontalCenter": true,
     "_isAbsVerticalCenter": true,
-    "_originalWidth": 0,
+    "_originalWidth": 1,
     "_originalHeight": 0,
     "_alignMode": 2,
     "_lockFlags": 0,
@@ -707,13 +707,13 @@
       "b": 255,
       "a": 255
     },
-    "_string": "点击开始游戏",
+    "_string": "点击「战斗」进入战斗阶段",
     "_horizontalAlign": 1,
     "_verticalAlign": 1,
-    "_actualFontSize": 36,
-    "_fontSize": 35,
+    "_actualFontSize": 41,
+    "_fontSize": 40,
     "_fontFamily": "Arial",
-    "_lineHeight": 40,
+    "_lineHeight": 50,
     "_overflow": 2,
     "_enableWrapText": true,
     "_font": null,
@@ -732,7 +732,7 @@
       "b": 0,
       "a": 255
     },
-    "_outlineWidth": 2,
+    "_outlineWidth": 4,
     "_enableShadow": false,
     "_shadowColor": {
       "__type__": "cc.Color",