refactor(platform): extract blurActiveElement to infrastructure module

- Centralize duplicated Platform.OS === 'web' blur logic across 16 components
- Add blurActiveElement utility to src/infrastructure/platform module
- Optimize MessageBubble and ImageSegment with React.memo custom comparators
- Add useMemo for computed values in MessageSegmentsRenderer
- Update DTO types with is_system_notice and notice_content fields
- Fix keyboard dismissal order in useChatScreen handleDismiss
- Simplify userStore follow/unfollow state updates
- Remove unnecessary TypeScript type assertions throughout codebase

src/services/errorHandler.ts

@@ -0,0 +1,196 @@
+/**
+ * 统一错误处理服务
+ * 
+ * 提供标准化的错误处理流程：
+ * 1. 错误分类（网络错误、认证错误、业务错误等）
+ * 2. 日志记录
+ * 3. 用户提示
+ * 4. 错误上报
+ * 
+ * 替代散落在代码中的 console.error + 手动 Alert 模式
+ */
+
+import { showPrompt } from './promptService';
+
+export enum AppErrorCode {
+  NETWORK_ERROR = 'NETWORK_ERROR',
+  AUTH_ERROR = 'AUTH_ERROR',
+  FORBIDDEN = 'FORBIDDEN',
+  NOT_FOUND = 'NOT_FOUND',
+  VALIDATION_ERROR = 'VALIDATION_ERROR',
+  SERVER_ERROR = 'SERVER_ERROR',
+  TIMEOUT = 'TIMEOUT',
+  UNKNOWN = 'UNKNOWN',
+}
+
+export interface AppError {
+  code: AppErrorCode;
+  message: string;
+  originalError?: unknown;
+  context?: string;
+  silent?: boolean;
+}
+
+const ERROR_MESSAGES: Record<AppErrorCode, string> = {
+  [AppErrorCode.NETWORK_ERROR]: '网络连接失败，请检查网络设置',
+  [AppErrorCode.AUTH_ERROR]: '登录已过期，请重新登录',
+  [AppErrorCode.FORBIDDEN]: '没有权限执行此操作',
+  [AppErrorCode.NOT_FOUND]: '请求的资源不存在',
+  [AppErrorCode.VALIDATION_ERROR]: '输入数据有误，请检查后重试',
+  [AppErrorCode.SERVER_ERROR]: '服务器错误，请稍后重试',
+  [AppErrorCode.TIMEOUT]: '请求超时，请稍后重试',
+  [AppErrorCode.UNKNOWN]: '操作失败，请稍后重试',
+};
+
+function classifyError(error: unknown): AppErrorCode {
+  if (!error) return AppErrorCode.UNKNOWN;
+
+  if (error instanceof Error) {
+    const message = error.message.toLowerCase();
+    
+    if (message.includes('network') || message.includes('fetch') || message.includes('econnrefused')) {
+      return AppErrorCode.NETWORK_ERROR;
+    }
+    if (message.includes('timeout') || message.includes('timed out')) {
+      return AppErrorCode.TIMEOUT;
+    }
+    if (message.includes('unauthorized') || message.includes('401') || message.includes('token')) {
+      return AppErrorCode.AUTH_ERROR;
+    }
+    if (message.includes('forbidden') || message.includes('403')) {
+      return AppErrorCode.FORBIDDEN;
+    }
+    if (message.includes('not found') || message.includes('404')) {
+      return AppErrorCode.NOT_FOUND;
+    }
+    if (message.includes('validation') || message.includes('400') || message.includes('422')) {
+      return AppErrorCode.VALIDATION_ERROR;
+    }
+    if (message.includes('500') || message.includes('502') || message.includes('503')) {
+      return AppErrorCode.SERVER_ERROR;
+    }
+  }
+
+  if (typeof error === 'object' && error !== null) {
+    const err = error as Record<string, unknown>;
+    const status = err.status || err.statusCode || err.code;
+    
+    if (status === 401) return AppErrorCode.AUTH_ERROR;
+    if (status === 403) return AppErrorCode.FORBIDDEN;
+    if (status === 404) return AppErrorCode.NOT_FOUND;
+    if (status === 400 || status === 422) return AppErrorCode.VALIDATION_ERROR;
+    if (typeof status === 'number' && status >= 500) return AppErrorCode.SERVER_ERROR;
+  }
+
+  return AppErrorCode.UNKNOWN;
+}
+
+export function createAppError(
+  error: unknown,
+  context?: string,
+  options?: { silent?: boolean; userMessage?: string }
+): AppError {
+  const code = classifyError(error);
+  return {
+    code,
+    message: options?.userMessage || ERROR_MESSAGES[code],
+    originalError: error,
+    context,
+    silent: options?.silent,
+  };
+}
+
+export interface ErrorHandlerOptions {
+  context?: string;
+  userMessage?: string;
+  silent?: boolean;
+  showErrorPrompt?: boolean;
+  logToConsole?: boolean;
+}
+
+/**
+ * 统一错误处理函数
+ * 
+ * 替代散落的 console.error + Alert 模式
+ * 
+ * @example
+ * // 之前
+ * } catch (error) {
+ *   console.error('加载帖子详情失败:', error);
+ * }
+ * 
+ * // 之后
+ * } catch (error) {
+ *   handleError(error, { context: '加载帖子详情' });
+ * }
+ */
+export function handleError(error: unknown, options: ErrorHandlerOptions = {}): AppError {
+  const {
+    context,
+    userMessage,
+    silent = false,
+    showErrorPrompt = false,
+    logToConsole = true,
+  } = options;
+
+  const appError = createAppError(error, context, { silent, userMessage });
+
+  if (logToConsole) {
+    const prefix = context ? `[${context}]` : '';
+    console.error(`${prefix} ${appError.message}`, error);
+  }
+
+  if (showErrorPrompt && !silent) {
+    showPrompt({
+      type: 'error',
+      title: context || '错误',
+      message: appError.message,
+      duration: 3000,
+    });
+  }
+
+  return appError;
+}
+
+/**
+ * 创建带上下文的错误处理器
+ * 
+ * @example
+ * const postErrorHandler = createErrorHandler('帖子');
+ * 
+ * } catch (error) {
+ *   postErrorHandler(error, { showErrorPrompt: true });
+ * }
+ */
+export function createErrorHandler(defaultContext: string) {
+  return (error: unknown, options: Omit<ErrorHandlerOptions, 'context'> = {}) => {
+    return handleError(error, { ...options, context: defaultContext });
+  };
+}
+
+/**
+ * 安全执行异步操作
+ * 
+ * @example
+ * const result = await safeAsync(
+ *   () => postService.getPost(id),
+ *   { context: '加载帖子' }
+ * );
+ * if (result.error) {
+ *   // 处理错误
+ * } else {
+ *   // 使用 result.data
+ * }
+ */
+export async function safeAsync<T>(
+  fn: () => Promise<T>,
+  options: ErrorHandlerOptions = {}
+): Promise<{ data: T | null; error: AppError | null }> {
+  try {
+    const data = await fn();
+    return { data, error: null };
+  } catch (error) {
+    const appError = handleError(error, options);
+    return { data: null, error: appError };
+  }
+}

src/services/index.ts

@@ -111,6 +111,11 @@ export {
 export { showPrompt } from './promptService';
 export { showConfirm } from './dialogService';
 
+// 统一错误处理服务
+export { handleError, createErrorHandler, safeAsync, createAppError } from './errorHandler';
+export type { AppError, ErrorHandlerOptions } from './errorHandler';
+export { AppErrorCode } from './errorHandler';
+
 // APK 更新检查服务
 export { apkUpdateService, checkForAPKUpdate, manualCheckForUpdate } from './apkUpdateService';
 export type { APKVersionInfo, VersionCheckResult } from './apkUpdateService';