feat(weightBilling): 优化按重量计费逻辑并完善界面展示

- 规格栏显示改为直接展示规格重量，去除单价/100克显示
- 新增最小计费重量常量 MIN_BILLABLE_WEIGHT，净重不足时阻止下单
- 下单时检测净重，低于最小计费重量时弹出提示并拦截
- 计算价格时按净重计算，单价基于规格价与规格重量的比值
- 本地明细中 eatNum 仅用于展示份数，不参与金额计算
- SettlementOrder 用实际食用重量 eatWeight 赋值 num 字段，配合重量栏显示逻辑调整

app/src/main/java/com/sw/dualscreen/activity/MainActivity.kt

@@ -107,6 +107,8 @@ class MainActivity : BaseActivity<ActivityMainBinding>() {
 
         const val WEIGHT_CHANGE_VALUE = 20
         const val WEIGHT_RESET_RECOGNIZE = 10
+        // 档口按重量计费的最小计费重量(克)，净重超过此值才计费/下单
+        const val MIN_BILLABLE_WEIGHT = 10
     }
 
     private val viewModel by viewModels<NetViewModelV2>()
@@ -912,8 +914,9 @@ class MainActivity : BaseActivity<ActivityMainBinding>() {
         val chargeMode = SPUtil.getInstance().get(GlobalKey.KEY_CHARGE_MODE, 0)
         //0-即放即取，1-余量计量
         val pickupMode = SPUtil.getInstance().get(GlobalKey.KEY_PICKUP_MODE, 0) ?: 0
-        if (eatNum <= 0) {
-            ToastUtils.showToast("您好，当前重量不足一份")
+        // 按重量计费：净重不足最小计费重量时，提示并拦截下单
+        if (eatWeight < MIN_BILLABLE_WEIGHT) {
+            ToastUtils.showToast("重量不足，无法下单")
             notEnoughOneBlock()
             return
         }

app/src/main/java/com/sw/dualscreen/adapter/FoodOrderAdapter.kt

@@ -39,8 +39,8 @@ class FoodOrderAdapter(list: MutableList<FoodItem>) :
             if (it.orderFrom == 2) {
                 binding.tvPriceNorm.text = if (it.specName.isNullOrBlank()) "${it.specWeight}克" else "${it.specName}/${it.specWeight}克"
             } else {
-                val foodPrice = it.foodPrice.format2String(2)
-                binding.tvPriceNorm.text = "${foodPrice}/100克"
+                // 营养秤结算：规格栏显示规格重量 specWeight
+                binding.tvPriceNorm.text = "${it.specWeight}克"
             }
             //if (it.specName.isNullOrBlank().not()) {
             //    binding.tvPriceFlag.text = "[${it.specName}]"

app/src/main/java/com/sw/dualscreen/model/response/v2/SettlementOrder.kt

@@ -49,5 +49,7 @@ private fun SettlementFoodItem.toFoodItem() = FoodItem(
     specName = specName,
     specWeight = specWeight?.toInt() ?: 0,
     eatNum = eatNum ?: 0,
-    price = price?.toDouble() ?: 0.0
+    price = price?.toDouble() ?: 0.0,
+    // 重量栏读取 num 字段，这里用实际食用重量 eatWeight 赋值
+    num = eatWeight ?: 0
 )

app/src/main/java/com/sw/dualscreen/presentation/MainScreenPresentation.kt

@@ -689,7 +689,7 @@ class MainScreenPresentation(
         Timber.tag(TAG) .d("addFoodToOrder: ${weight == lastAddWeight}")
 //        if (weight == lastAddWeight) return
         lastAddWeight = weight
-        if (weight <= 10) {
+        if (weight <= MainActivity.MIN_BILLABLE_WEIGHT) {
             //0-即放即取，1-余量计量
             mealPickupMode = SPUtil.getInstance().get(GlobalKey.KEY_PICKUP_MODE, 0) ?: 0
             if (foodOrderList.isNotEmpty() && mealPickupMode == 1) {
@@ -702,10 +702,17 @@ class MainScreenPresentation(
             }
             return
         }
-        //val foodPrice = if (isMember) foodInfo.vipPrice else foodInfo.specPrice
-        val foodPrice = (foodInfo.specPrice ?: 0.0) * memberDiscount
+        // 按重量计价：每克单价 = 规格价 / 规格重量，再按会员折扣折算
+        // 单价 = specPrice / specWeight，金额 = 当前秤上净重 × 单价 × 会员折扣
+        val specWeight = foodInfo.specWeight ?: 0.0
+        val specPrice = foodInfo.specPrice ?: 0.0
+        val price = if (specWeight > 0.0) {
+            weight * (specPrice / specWeight) * memberDiscount
+        } else {
+            0.0
+        }
+        // eatNum 仅用于本地明细展示（份数），不再参与金额计算
         val eatNum = activity.getEatNum(weight.toDouble(), foodInfo.specWeight)
-        val price = eatNum * foodPrice
         if (foodOrderList.isNotEmpty() && mealPickupMode == 1) {
             val last = foodOrderList.last()
             if (last.isLocalData) {