feat(奖励详情): 实现优惠券详情页面的API对接和交互逻辑

- 对接获取优惠券详情和兑换优惠券的API
- 根据API响应动态渲染页面内容
- 添加积分不足状态下的按钮禁用和样式变化
- 优化页面加载和用户交互流程

@@ -19,6 +19,7 @@ declare module 'vue' {
     NutDialog: typeof import('@nutui/nutui-taro')['Dialog']
     NutImagePreview: typeof import('@nutui/nutui-taro')['ImagePreview']
     NutInput: typeof import('@nutui/nutui-taro')['Input']
+    NutLoading: typeof import('@nutui/nutui-taro')['Loading']
     NutPicker: typeof import('@nutui/nutui-taro')['Picker']
     NutPopup: typeof import('@nutui/nutui-taro')['Popup']
     NutRow: typeof import('@nutui/nutui-taro')['Row']