refactor: 移动端升级 Vue3 + uView Plus

将 lilishop-uniapp 从 Vue2/uView 1.6 迁移到 Vue3/uview-plus，优先支持 H5/微商城与微信小程序；移除 vendored uview-ui，改用 npm 依赖、Vuex4 与迁移脚本/补丁，并补充 VUE3_MIGRATION.md 回归清单。

Co-authored-by: Cursor <cursoragent@cursor.com>

pages/cart/payment/payOrder.vue

@@ -10,7 +10,7 @@
         </p>
         <p class="ptips">
           支付金额
-          <span>¥{{ cashierParams.price | unitPrice }}</span>
+          <span>¥{{unitPrice(cashierParams.price) }}</span>
         </p>
       </div>
     </div>
@@ -31,7 +31,7 @@
             </div>
             <div v-if="item == 'WALLET'">
               <u-icon class="method_icon" name="red-packet-fill" color="#dd6161" size="80"></u-icon>
-              <span class="method_name">余额支付(当前余额：¥{{ walletValue | unitPrice }})</span>
+              <span class="method_name">余额支付(当前余额：¥{{unitPrice(walletValue) }})</span>
             </div>
           </div>
           <div class="col3" @click="awaitPay(item)" textAlign="right">