数量加减：同城/跨城/现场取货确认页加减号不再置灰；点减到低于起购时 toast，数量仍可降到 1（不能到 0）。

支付后返回：支付成功进详情带 from=pay；返回一律 switchTab 首页（失败则 reLaunch），避免栈只有一页时 navigateBack 退出小程序。订单列表返回同样加固。

apps/mini-user/src/pages/order-confirm-pickup/index.tsx

@@ -75,11 +75,12 @@ export default function OrderConfirmPickupPage() {
   const canSubmit = !!preview && quantityOk && !loading && !previewLoading;
 
   function updateQuantity(next: number) {
-    if (next < 1) return;
     if (next < minQty) {
       const tip = `现场提货至少购买 ${minQty} 瓶`;
       toast(tip);
       setMsg(tip);
+      if (next < 1) return;
+      setQuantity(next);
       return;
     }
     setQuantity(next);
@@ -101,8 +102,12 @@ export default function OrderConfirmPickupPage() {
 
   async function submit() {
     if (!canSubmit) {
-      if (!quantityOk) setMsg(`现场提货至少购买 ${minQty} 瓶`);
-      return;
+      if (!quantityOk) {
+        const tip = `现场提货至少购买 ${minQty} 瓶`;
+        setMsg(tip);
+        toast(tip);
+        return;
+      }
     }
 
     const returnPath = `/pages/order-confirm-pickup/index?productId=${productId}&qty=${quantity}`;
@@ -191,8 +196,8 @@ export default function OrderConfirmPickupPage() {
                 <Text>购买数量</Text>
                 <View className="order-qty-controls">
                   <View
-                    className={`order-qty-btn${quantity <= minQty ? ' order-qty-btn--disabled' : ''}`}
-                    onClick={() => updateQuantity(Math.max(minQty, quantity - 1))}
+                    className="order-qty-btn"
+                    onClick={() => updateQuantity(quantity - 1)}
                   >
                     <Text>−</Text>
                   </View>

apps/mini-user/src/pages/order-confirm/index.tsx

@@ -167,14 +167,14 @@ export default function OrderConfirmPage() {
     : '';
 
   function updateQuantity(next: number) {
-    if (next < 1) return;
     if (next < minQty) {
       const tip = isCross
         ? `跨城配送至少购买 ${minQty} 瓶（1箱）`
         : `同城配送至少购买 ${minQty} 瓶`;
       toast(tip);
       setMsg(tip);
-      setQuantity(Math.max(1, next));
+      if (next < 1) return;
+      setQuantity(next);
       return;
     }
     setQuantity(next);
@@ -352,7 +352,7 @@ export default function OrderConfirmPage() {
                 <Text>购买数量</Text>
                 <View className="order-qty-controls">
                   <View
-                    className={`order-qty-btn${quantity <= 1 ? ' order-qty-btn--disabled' : ''}`}
+                    className="order-qty-btn"
                     onClick={() => updateQuantity(quantity - 1)}
                   >
                     <Text>−</Text>

apps/mini-user/src/pages/order-detail/index.tsx

@@ -181,12 +181,15 @@ export default function OrderDetailPage() {
       <SubPageHeader
         title="订单详情"
         onBack={() => {
-          const pages = Taro.getCurrentPages();
-          if (pages.length > 1) {
-            Taro.navigateBack();
+          // 支付完成后 reLaunch 进详情：栈仅一页时 navigateBack 会退出小程序，统一回首页
+          const fromPay = String(router.params.from || '') === 'pay';
+          if (fromPay || Taro.getCurrentPages().length <= 1) {
+            Taro.switchTab({ url: '/pages/home/index' }).catch(() => {
+              Taro.reLaunch({ url: '/pages/home/index' });
+            });
             return;
           }
-          Taro.switchTab({ url: '/pages/home/index' });
+          Taro.navigateBack();
         }}
         right={<ShareNavButton payload={sharePayload} />}
       />

apps/mini-user/src/pages/orders/index.tsx

@@ -95,7 +95,11 @@ export default function OrdersPage() {
     <PageShell variant="sub" className="orders-page">
       <SubPageHeader
         title="我的订单"
-        onBack={() => Taro.switchTab({ url: '/pages/home/index' })}
+        onBack={() => {
+          Taro.switchTab({ url: '/pages/home/index' }).catch(() => {
+            Taro.reLaunch({ url: '/pages/home/index' });
+          });
+        }}
       />
       <View className="order-tabs">
         {TABS.map((t) => (

apps/mini-user/src/pages/pay/index.tsx

@@ -144,10 +144,10 @@ export default function PayPage() {
         toast('支付成功', 'success');
       }
       if (deliveryType === 'ON_SITE_PICKUP') {
-        // 现场提货支付即完成 → 订单详情（已完成）；reLaunch 清掉商品详情栈
-        Taro.reLaunch({ url: `/pages/order-detail/index?id=${orderId}` });
+        // 现场提货支付即完成 → 订单详情；from=pay 返回强制回首页，避免 navigateBack 退出小程序
+        Taro.reLaunch({ url: `/pages/order-detail/index?id=${orderId}&from=pay` });
       } else {
-        Taro.reLaunch({ url: '/pages/orders/index?tab=paid' });
+        Taro.reLaunch({ url: '/pages/orders/index?tab=paid&from=pay' });
       }
     } catch (e) {
       if (isWechatAuthRequiredError(e)) {