- gateway/internal/shared/: 新建 shared/auth 和 shared/logging 包 - shared/logging: LogEntry/Logger/NewLogger/sanitizeFields, 7个golden output测试 - shared/auth: ExtractBearerToken/HasExternalQueryKey/WriteAuthError/AuditEvent, 8个契约测试 - docs/plans/2026-04-21-shared-auth-logging-analysis.md: P4-A完整分析文档 迁移顺序: logging(第一步) -> auth基础(第二步) -> audit(第三步) -> 契约测试(第四步) 共享边界: JWT验证/token状态查询/授权策略/BruteForce保持服务特有