fix(viewmodel): 修复切换 tab 返回后数据消失及 loading 不消失的问题

切换 tab 时重置对方的 StateFlow 状态为初始值，避免 repeatOnLifecycle
重启后 replay 残留状态导致 UI 异常覆盖或 loading 无法关闭

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/src/main/java/com/shuwei/dish/match/db/DbViewModel.kt

@@ -36,7 +36,9 @@ class DbViewModel : ViewModel() {
 
     private val _cookFoodListState = MutableStateFlow<MutableList<CookFoodEntity>?>(null)
     val cookFoodListState: StateFlow<MutableList<CookFoodEntity>?> = _cookFoodListState.asStateFlow()
-
+    fun resetCookFoodList() {
+        _cookFoodListState.value = null
+    }
     fun getCookFoodList(
         cookMode: Int,
         dinnerType: String = "0"

app/src/main/java/com/shuwei/dish/match/net/NetViewModel.kt

@@ -72,6 +72,9 @@ class NetViewModel(
      */
     private val _samplingListState = MutableStateFlow<UiState<MutableList<FoodRecord>?>>(UiState.Idle)
     val samplingListState: StateFlow<UiState<MutableList<FoodRecord>?>> = _samplingListState.asStateFlow()
+    fun resetSamplingListState() {
+        _samplingListState.value = UiState.Idle
+    }
 
     /**
      * 查询采样数据列表

app/src/main/java/com/shuwei/dish/match/ui/SamplingListActivity.kt

@@ -307,13 +307,18 @@ class SamplingListActivity : BaseActivity() {
     @SuppressLint("NotifyDataSetChanged")
     fun refreshLocalData() {
         showLoading()
+        appViewModel.resetCookFoodList()
         getCookFoodList()
     }
 
     private fun requestData(isCooking: Boolean) {
         if (isCooking) {
+            // 清除上次网络请求的残留状态
+            netViewModel.resetSamplingListState()
             refreshLocalData()
         } else {
+            // 同理，清除本地数据残留状态
+            appViewModel.resetCookFoodList()
             pageNo = 1
             getSamplingList()
         }