refactor(fragment): 改用回调方式查询菜品列表，修复刷新卡死问题

- FoodListFragment 改用 searchFoodListWithCallback 替代 SharedFlow collect，
  彻底解决下拉/上拉因数据相同导致不触发的问题
- NetViewModel 新增 searchFoodListWithCallback 回调版本
- CookingModeActivity loadFragment 改为 show/hide 方式，切换餐次不重建 Fragment
- 修复数据为空时未调用 finishRefresh 导致加载动画卡死的问题
- 新增 fragment-ktx 依赖，支持 by viewModels()

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

gradle/libs.versions.toml

@@ -16,6 +16,7 @@ junitVersion = "1.1.5"
 espressoCore = "3.5.1"
 appcompat = "1.6.1"
 kotlinGradlePlugin = "2.0.21"
+fragmentKtx = "1.8.6"
 lifecycleRuntimeKtx = "2.8.7"
 lifecycleViewmodelKtx = "2.8.7"
 loggingInterceptor = "4.9.1"
@@ -36,6 +37,7 @@ flexbox = "3.0.0"
 [libraries]
 android-core = { module = "com.google.zxing:android-core", version.ref = "androidCore" }
 androidx-activity-ktx = { module = "androidx.activity:activity-ktx", version.ref = "activityKtx" }
+androidx-fragment-ktx = { module = "androidx.fragment:fragment-ktx", version.ref = "fragmentKtx" }
 androidx-lifecycle-viewmodel-ktx = { module = "androidx.lifecycle:lifecycle-viewmodel-ktx", version.ref = "lifecycleViewmodelKtx" }
 androidx-lifecycle-runtime-ktx = { module = "androidx.lifecycle:lifecycle-runtime-ktx", version.ref = "lifecycleRuntimeKtx" }
 androidx-room-ktx = { module = "androidx.room:room-ktx", version.ref = "roomRuntime" }