fix: config.vue日期选择器改回原生picker

u-datetime-picker的v-model不支持表达式，在v-for循环中改用原生picker

pages/config/config.vue

@@ -115,16 +115,12 @@
 
           <view class="date-row">
             <text class="sub-label">建仓日期</text>
-            <u-datetime-picker
-              v-model="item.dateValue || Date.now()"
-              mode="date"
-              @confirm="(e) => { item.date = e.value; item.dateValue = e.value; }"
-            >
+            <picker mode="date" :value="item.date" @change="(e) => onDateChange(e, index)">
               <view class="date-picker-display">
                 <text>{{ item.date || '请选择日期' }}</text>
                 <u-icon name="calendar" size="16" color="#9CA3AF"></u-icon>
               </view>
-            </u-datetime-picker>
+            </picker>
           </view>
 
         </view>