feat: 用户体验优化 — 首页加载/继续记账/登录恢复

## 首页加载优化
- 分级加载：首屏只请求 overview + recentTx（2个请求）
- 数据新鲜度：30秒内不重复请求
- 次要数据异步加载：budget + todayData
- 非关键数据后台加载：userInfo + notifications

## 继续记账功能
- SaveSuccess 组件新增「继续记一笔」按钮
- 新增模式显示继续按钮，编辑模式自动返回
- 继续记账时保留分类和日期，清空金额和备注

## 登录失败恢复
- 登录重试机制：最多3次，间隔1秒
- 失败后显示提示而非静默等待

## 群组账单逻辑修正
- 群组账单 = 所有群组成员的个人账单之和
- 修改查询：WHERE user_id IN (群组成员)

client/src/pages/bills/index.vue

@@ -27,7 +27,7 @@
     <!-- 筛选面板 -->
     <FilterPanel v-if="showFilter" :initialFilters="advancedFilters" @close="showFilter = false" @apply="onFilterApply" />
 
-    <view class="tx-list" v-if="!txStore.loading || txList.length > 0">
+    <view class="tx-list" v-if="!loading || txList.length > 0">
       <view v-for="group in groupedTx" :key="group.date" class="date-group">
         <view class="group-header">
           <text class="group-date">{{ group.label }}</text>
@@ -49,7 +49,7 @@
       </view>
     </view>
 
-    <view class="tx-list" v-if="txStore.loading && txList.length === 0">
+    <view class="tx-list" v-if="loading && txList.length === 0">
       <view v-for="g in 2" :key="g" class="date-group">
         <view class="group-header">
           <Skeleton width="120rpx" height="26rpx" variant="text" />
@@ -66,7 +66,7 @@
       </view>
     </view>
 
-    <view class="loading-more" v-if="txStore.loading && txList.length > 0">
+    <view class="loading-more" v-if="loading && txList.length > 0">
       <text class="loading-text">加载中...</text>
     </view>
 
@@ -79,7 +79,7 @@
       <text class="state-text">加载失败，下拉刷新重试</text>
     </view>
 
-    <view class="empty" v-if="txList.length === 0 && !txStore.loading && !loadError">
+    <view class="empty" v-if="txList.length === 0 && !loading && !loadError">
       <text class="empty-text">暂无账单记录</text>
     </view>
   </view>
@@ -91,7 +91,7 @@ import { onShow, onReachBottom, onPullDownRefresh } from '@dcloudio/uni-app'
 import { useUserStore } from '@/stores/user'
 import { useGroupStore } from '@/stores/group'
 import { waitForReady } from '@/utils/app-ready'
-import { getTransactions } from '@/api/transaction'
+import { getTransactions, deleteTransaction } from '@/api/transaction'
 import TransactionItem from '@/components/TransactionItem/TransactionItem.vue'
 import Icon from '@/components/Icon/Icon.vue'
 import Skeleton from '@/components/Skeleton/Skeleton.vue'
@@ -102,6 +102,7 @@ import type { FilterParams } from '@/api/filter'
 
 const userStore = useUserStore()
 const groupStore = useGroupStore()
+const loading = ref(false)
 const filterType = ref('all')
 const page = ref(1)
 const pageSize = 20
@@ -172,6 +173,7 @@ async function loadTx(reset = false, silent = false) {
   if (af.maxAmount) params.maxAmount = af.maxAmount
   if (af.keyword) params.keyword = af.keyword
   try {
+    loading.value = true
     loadError.value = false
     const data = await getTransactions(params)
     // 丢弃过期请求的结果
@@ -188,6 +190,8 @@ async function loadTx(reset = false, silent = false) {
     if (seq !== loadSeq) return
     console.error('Load bills error:', e)
     loadError.value = true
+  } finally {
+    if (seq === loadSeq) loading.value = false
   }
 }
 
@@ -216,7 +220,7 @@ async function onDelete(item: any) {
     success: async (res) => {
       if (res.confirm) {
         try {
-          await txStore.deleteTransaction(item.id)
+          await deleteTransaction(item.id)
           txList.value = txList.value.filter(t => t.id !== item.id)
           total.value--
           // 更新筛选金额
@@ -236,7 +240,7 @@ async function onDelete(item: any) {
 
 // 触底加载更多
 onReachBottom(() => {
-  if (noMore.value || txStore.loading) return
+  if (noMore.value || loading) return
   page.value++
   loadTx(false)
 })