995e0664d5
Add USER_BANNED (403) handling across auth flow: - Extend FetchCurrentUserResult and RefreshResult with 'banned' type - Detect USER_BANNED errorCode in authService and api client - Clear token and show "账号已被封禁，请联系管理员" on ban detection - Throw non-network refresh errors up to caller instead of silent clear Add optional auth path support: - Extract optional auth path prefixes to optionalAuthPaths.ts - Handle 401 on optional auth GET endpoints by clearing expired token and retrying as guest (without triggering navigateToLogin) - Export helpers for existing consumers Handle backend behavior change: - Guest logout now returns 401 instead of 200; treat as silent success Add tests for optional auth path logic.