重构认证授权逻辑，集中到 auth 包中

web/handlers/channel.go

@@ -198,10 +198,7 @@ type RemoveChannelsReq struct {
 
 func RemoveChannels(c *fiber.Ctx) error {
 	// 检查权限
-	authCtx, err := auth.Protect(c, []auth.PayloadType{
-		auth.PayloadUser,
-		auth.PayloadSecuredServer,
-	}, []string{})
+	authCtx, err := auth.Protect(c, []auth.PayloadType{auth.PayloadUser, auth.PayloadInternalServer}, []string{})
 	if err != nil {
 		return err
 	}