refactor(app): 重构应用主题和页面结构

- 移除动态主题切换功能，改为全局统一深色主题
- 实现自定义TabBar组件替换原生tabBar，解决iOS闪白问题
- 创建main容器页面统一管理三个tab页面的生命周期和状态
- 将所有页面的onShow/onHide等生命周期方法迁移到子组件内部
- 更新页面路径从index改为main，并调整路由跳转逻辑
- 移除theme-mixin和相关主题工具函数
- 统一页面背景色设置，优化用户体验一致性

pages/card/card.vue

@@ -1,5 +1,5 @@
 <template>
-  <view :class="themeClass" class="page-container card-page">
+  <view class="page-container card-page">
     <view class="card-nav" :style="{ paddingTop: (statusBarHeight + 12) + 'px' }">
       <view class="step-back" @click="goBack">
         <text class="step-back-arrow">‹</text>
@@ -42,12 +42,10 @@ import DrinkCard from '../../components/DrinkCard.vue'
 import client from '../../common/api'
 import { calcStandardCups, unitToMl } from '../../common/utils'
 import { DRINK_CATEGORIES, FOOD_CATEGORIES, DRINK_QUOTES, FEELINGS } from '../../common/constants'
-import themeMixin from '../../common/theme-mixin'
 
 const UNIT_NAMES = { ml: 'ml', liang: '两', bottle: '瓶', cup: '杯', can: '听', shot: 'shot' }
 
 export default {
-  mixins: [themeMixin],
   components: { DrinkCard },
   data() {
     const sysInfo = uni.getSystemInfoSync()
@@ -761,7 +759,7 @@ export default {
       })
     },
     closeToHome() {
-      uni.switchTab({ url: '/pages/index/index' })
+      uni.reLaunch({ url: '/pages/main/main?tab=0' })
     },
     _doBack() {
       console.log('_doBack called, pages:', getCurrentPages().length)
@@ -769,12 +767,12 @@ export default {
         uni.navigateBack({
           fail: (err) => {
             console.error('navigateBack fail:', err)
-            uni.reLaunch({ url: '/pages/index/index' })
+            uni.reLaunch({ url: '/pages/main/main?tab=0' })
           }
         })
       } else {
         console.log('no pages to go back to, reLaunch to index')
-        uni.reLaunch({ url: '/pages/index/index' })
+        uni.reLaunch({ url: '/pages/main/main?tab=0' })
       }
     }
   },
@@ -788,7 +786,7 @@ export default {
       : '今晚的酒局记录 - 碰盏日记'
     return {
       title,
-      path: '/pages/index/index',
+      path: '/pages/main/main?tab=0',
       imageUrl: this.posterPath || undefined
     }
   },