Module layer 

SaTokenLayer Fairing: runs shared run_auth_flow, then sets SaTokenContext / clears after response. SaTokenLayer Fairing：执行统一的 run_auth_flow，设置 SaTokenContext，响应后清理。

Structs

SaTokenLayer

Rocket Fairing using RocketCapturedRequest + run_auth_flow (rocket-core pipeline). 使用 RocketCapturedRequest + run_auth_flow（rocket-core 流水线）的 Fairing。