Function run_auth_flow 

pub async fn run_auth_flow<R>(
    req: &R,
    manager: &SaTokenManager,
    path_config: Option<&PathAuthConfig>,
) -> AuthFlowResult
where
    R: SaRequest,

Full auth pipeline: extract_token → optional PathAuthConfig via process_auth, else default check → create_context. 完整鉴权流水线：extract_token → 若有 PathAuthConfig 则 process_auth，否则默认校验 → create_context。

Pass path_config: None for “validate token if present, no path-based reject”. path_config 为 None 时表示：有 token 则校验并填上下文，不按路径规则拒绝。