fix(chat): 修复加载状态显示和API响应判断逻辑

- 修复ChatActivity中加载进度条和占位图标切换逻辑
- 初始化ChatVM中loading状态为false避免空值问题
- 修复CompositeLayupResultVM中API成功判断条件从success改为code==200
- 修复CompositeLayupTaskVM中API成功判断条件从success改为code==200

app/src/main/java/com/nova/brain/glass/ui/ChatActivity.kt

@@ -42,6 +42,9 @@ class ChatActivity : BaseListFormLayoutNormalActivity<ChatItem, ChatVM, Activity
         }
 
         // loading=true：显示旋转进度；loading=false：显示静态占位图
+        val isLoading = viewModel.loading.value ?: false
+        binding.loadingProgress.visibility = if (isLoading) View.VISIBLE else View.GONE
+        binding.loadingIdleIcon.visibility = if (isLoading) View.GONE else View.VISIBLE
         viewModel.loading.observe(this) { loading ->
             binding.loadingProgress.visibility = if (loading) View.VISIBLE else View.GONE
             binding.loadingIdleIcon.visibility = if (loading) View.GONE else View.VISIBLE

app/src/main/java/com/nova/brain/glass/viewmodel/ChatVM.kt

@@ -30,7 +30,7 @@ class ChatVM : BaseListViewModel<ChatItem>() {
     }
 
     val result = MutableLiveData<String>()
-    val loading = MutableLiveData<Boolean>()
+    val loading = MutableLiveData(false)
     /** 末尾始终保留一个占位 item（SPACER_ID），高度 = RecyclerView 高度，用于支持最新 item 滚到顶部 */
     val chatItems: MutableList<ChatItem> = mutableListOf(ChatItem(SPACER_ID, "", ""))
 

app/src/main/java/com/nova/brain/glass/viewmodel/CompositeLayupResultVM.kt

@@ -47,7 +47,7 @@ class CompositeLayupResultVM : BaseListViewModel<ItemItem>() {
             .subscribeOn(Schedulers.io())
             .observeOn(AndroidSchedulers.mainThread())
             .subscribe({ response ->
-                if (response.success && response.data != null) {
+                if (response.code==200 && response.data != null) {
                     recognizeResult.value = response.data
                     resultState.value = CompositeLayupResultState.SUCCESS
                 } else {

app/src/main/java/com/nova/brain/glass/viewmodel/CompositeLayupTaskVM.kt

@@ -83,7 +83,7 @@ class CompositeLayupTaskVM : BaseListViewModel<ItemItem>() {
             .observeOn(AndroidSchedulers.mainThread())
             .subscribe({ response ->
                 val result = response.data
-                if (response.success && result != null) {
+                if (response.code==200 && result != null) {
                     recognizeResult.value = result
                     lastRecognizeFinished = result.finished
                     recognizeState.value = CompositeLayupRecognizeState.SUCCESS