refactor: 优化ViewModel和工具类

- 优化AuthViewModel认证ViewModel
- 优化MyMemoirViewModel回忆录ViewModel
- 扩展TextUtils工具类

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

@@ -338,16 +338,17 @@ class AuthViewModel(private val context: Context) : ViewModel() {
     }
     
     /**
-     * 验证码登录
+     * 验证码登录/注册（统一接口）
+     * 如果用户不存在，会自动注册（需要提供nickname）
      */
-    fun loginWithSms(phone: String, code: String, agreedToTerms: Boolean) {
+    fun loginWithSms(phone: String, code: String, agreedToTerms: Boolean, nickname: String? = null) {
         viewModelScope.launch {
             _isLoading.value = true
             _errorMessage.value = null
             _successMessage.value = null
             _operationResult.value = null
             
-            val result = authService.loginWithSms(phone, code, agreedToTerms)
+            val result = authService.loginWithSms(phone, code, agreedToTerms, nickname)
             
             result.fold(
                 onSuccess = { tokenResponse ->
@@ -365,21 +366,35 @@ class AuthViewModel(private val context: Context) : ViewModel() {
                     
                     // 显示成功消息
                     val userNickname = _currentUser.value?.nickname ?: "用户"
-                    _successMessage.value = "登录成功！"
+                    val isNewUser = nickname != null && nickname.isNotBlank()
+                    _successMessage.value = if (isNewUser) "注册成功！" else "登录成功！"
                     _operationResult.value = OperationResult(
                         success = true,
-                        message = "登录成功",
-                        details = "欢迎回来，${userNickname}！正在跳转..."
+                        message = if (isNewUser) "注册成功" else "登录成功",
+                        details = if (isNewUser) {
+                            "账号已创建，欢迎加入岁月史书！正在跳转..."
+                        } else {
+                            "欢迎回来，${userNickname}！正在跳转..."
+                        }
                     )
                 },
                 onFailure = { exception ->
                     val errorMsg = exception.message ?: "登录失败"
                     _errorMessage.value = errorMsg
                     _isLoggedIn.value = false
+                    
+                    // 检查是否是首次登录需要昵称的错误
+                    val needsNickname = errorMsg.contains("首次登录需要设置昵称") || 
+                                       errorMsg.contains("需要设置昵称")
+                    
                     _operationResult.value = OperationResult(
                         success = false,
-                        message = "登录失败",
-                        details = errorMsg
+                        message = if (needsNickname) "需要设置昵称" else "登录失败",
+                        details = if (needsNickname) {
+                            "这是您首次登录，请设置一个昵称"
+                        } else {
+                            errorMsg
+                        }
                     )
                 }
             )

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

@@ -21,6 +21,7 @@ class MyMemoirViewModel(
 ) : ViewModel() {
     
     val chapters = chapterRepository.getAllChapters()
+    val chapterDtos = MutableStateFlow<List<com.huaga.life_echo.network.models.ChapterDto>>(emptyList())
     val selectedChapter = MutableStateFlow<Chapter?>(null)
     val isLoading = MutableStateFlow(false)
     val error = MutableStateFlow<String?>(null)
@@ -64,9 +65,12 @@ class MyMemoirViewModel(
             try {
                 val result = apiService.getChapters()
                 result.fold(
-                    onSuccess = { chapterDtos ->
+                    onSuccess = { chapterDtosFromApi ->
+                        // 保存ChapterDto（包含images信息）
+                        chapterDtos.value = chapterDtosFromApi
+                        
                         // 转换为本地Chapter实体并保存
-                        val chapters = chapterDtos.map { dto ->
+                        val chapters = chapterDtosFromApi.map { dto ->
                             Chapter(
                                 id = dto.id,
                                 title = dto.title,

app-android/app/src/main/java/com/huaga/life_echo/utils/TextUtils.kt

@@ -65,4 +65,36 @@ object TextUtils {
         val quotePattern = Regex("""["'](.*?)["']""")
         return quotePattern.findAll(text).map { it.groupValues[1] }.toList()
     }
+    
+    /**
+     * 移除图片占位符
+     * 如果没有图片，移除所有{{{{IMAGE:...}}}}和{{IMAGE:...}}格式的占位符
+     * 同时确保每个段落之间有空行
+     * @param content 原始内容
+     * @param hasImages 是否有图片
+     * @return 处理后的内容
+     */
+    fun removeImagePlaceholders(content: String?, hasImages: Boolean = false): String {
+        if (content.isNullOrBlank()) return ""
+        
+        var processed = if (!hasImages) {
+            // 移除所有{{{{IMAGE:...}}}}格式的占位符（四个大括号）
+            content.replace(Regex("\\{\\{\\{\\{IMAGE:[^}]+\\}\\}\\}\\}"), "")
+                // 移除所有{{IMAGE:...}}格式的占位符（两个大括号）
+                .replace(Regex("\\{\\{IMAGE:[^}]+\\}\\}"), "")
+                .trim()
+        } else {
+            content
+        }
+        
+        // 确保每个段落之间有空行
+        // 将单个换行符（非空行后跟非空行）替换为双换行符
+        // 但保留已有的双换行符或更多换行符
+        processed = processed.replace(Regex("([^\n\\r])\\r?\\n([^\n\\r])"), "$1\n\n$2")
+        
+        // 清理多余的空行（连续3个或以上的换行符替换为2个）
+        processed = processed.replace(Regex("\n{3,}"), "\n\n")
+        
+        return processed.trim()
+    }
 }