fix: 解决消息重复问题

app-android/app/src/main/java/com/huaga/life_echo/data/repository/MessageRepository.kt

@@ -19,10 +19,11 @@ class MessageRepository(
         return messageDao.getMessagesByConversationId(conversationId)
     }
     
-    /** 从 [conversationApi] 拉取消息并写入本地数据库 */
+    /** 从 [conversationApi] 拉取消息并写入本地数据库，以服务端为准替换该会话的本地消息，避免与本地临时消息重复显示 */
     suspend fun syncMessages(conversationId: String) {
         val result = conversationApi.getMessages(conversationId)
         result.getOrNull()?.let { messages ->
+            messageDao.deleteMessagesByConversationId(conversationId)
             val dbMessages = messages.map { dto ->
                 Message(
                     id = dto.id,

app-android/app/src/main/java/com/huaga/life_echo/ui/viewmodel/CreateMemoryViewModel.kt

@@ -658,37 +658,39 @@ class CreateMemoryViewModel(
                     isTyping.value = false
                 }
 
-                conversationId.value?.let { id ->
-                    val messageTimestamp = System.currentTimeMillis()
-                    val aiMessage = Message(
-                        id = "ai_${System.currentTimeMillis()}_$index",
-                        conversationId = id,
-                        content = text,
-                        senderType = "assistant",
-                        timestamp = messageTimestamp,
-                        messageType = "text"
-                    )
-                    viewModelScope.launch {
-                        messageRepository.insertMessage(aiMessage)
-                        updateConversationLatestMessage(
-                            conversationId = id,
-                            messagePreview = text,
-                            timestamp = messageTimestamp,
-                        )
-                    }
-                }
-
+                // 用 [SPLIT] 拼接多条，与后端约定一致，便于 UI 按 [SPLIT] 拆成多个气泡
                 if (index == 0) {
                     agentResponse.value = text
                 } else {
-                    agentResponse.value += "\n\n$text"
+                    agentResponse.value += "[SPLIT]$text"
                 }
 
+                // 仅在完整收到一条 AI 回复时插入一次，避免按 index 多次插入导致同一条显示多遍
                 if (index >= total - 1) {
                     isStreaming.value = false
                     streamingText.value = ""
                     isTyping.value = false
                     conversationRealtime.setGenerating(false)
+                    conversationId.value?.let { id ->
+                        val messageTimestamp = System.currentTimeMillis()
+                        val fullContent = agentResponse.value
+                        val aiMessage = Message(
+                            id = "ai_${System.currentTimeMillis()}",
+                            conversationId = id,
+                            content = fullContent,
+                            senderType = "assistant",
+                            timestamp = messageTimestamp,
+                            messageType = "text"
+                        )
+                        viewModelScope.launch {
+                            messageRepository.insertMessage(aiMessage)
+                            updateConversationLatestMessage(
+                                conversationId = id,
+                                messagePreview = fullContent,
+                                timestamp = messageTimestamp,
+                            )
+                        }
+                    }
                 }
             }
             MessageType.agent_response_start -> {