fix: 更新配置和代码逻辑以提升稳定性和可读性

- 在 manifest.json 和 project.config.json 中启用 postcss 和 enhance 设置
- 在多个 Vue 组件中优化空值处理逻辑，确保更健壮的代码执行
- 调整样式和布局以提升用户体验

pages/product/product/promotion/-promotion-assemble-promotions.vue

@@ -162,7 +162,7 @@ function refreshCountdown(list = promotionList.value) {
 }
 
 function padTime(val: number | undefined) {
-  return String(val ?? 0).padStart(2, '0')
+  return String(val != null ? val : 0).padStart(2, '0')
 }
 
 function countdownDisplayHours(index: number) {

pages/product/shopPage.vue

@@ -317,7 +317,7 @@ function initPageData() {
     num: storeId.value,
   })
     .then((res) => {
-      const payload = res?.data ?? res
+      const payload = res?.data != null ? res.data : res
       const result = payload?.result
       const pageDataStr = result?.pageData
       if (!isPageDataSuccess(payload) || !pageDataStr) {
@@ -571,31 +571,31 @@ onMounted(() => {
     min-height: 56rpx;
   }
 
-  .store-name {
-    width: 100%;
-    font-size: 34rpx;
-    color: #333;
-    letter-spacing: 1rpx;
-    font-weight: bold;
-    text-align: left;
-  }
-
-  .store-name-text {
-    overflow: hidden;
-    text-overflow: ellipsis;
-    white-space: nowrap;
-    display: block;
-    padding: 0 150rpx 0 0;
-    box-sizing: border-box;
-  }
-
-  .store-message {
-    display: flex;
-    align-items: center;
-    justify-content: flex-start;
-    flex-wrap: nowrap;
-    margin-top: 12rpx;
-    font-size: 24rpx;
+  .store-name {
+    width: 100%;
+    font-size: 34rpx;
+    color: #333;
+    letter-spacing: 1rpx;
+    font-weight: bold;
+    text-align: left;
+  }
+
+  .store-name-text {
+    overflow: hidden;
+    text-overflow: ellipsis;
+    white-space: nowrap;
+    display: block;
+    padding: 0 150rpx 0 0;
+    box-sizing: border-box;
+  }
+
+  .store-message {
+    display: flex;
+    align-items: center;
+    justify-content: flex-start;
+    flex-wrap: nowrap;
+    margin-top: 12rpx;
+    font-size: 24rpx;
     color: #999;
   }