-- Additive migration: centralized admin control system
-- Adds scheduled feature windows and multi-level referral commission configuration.
-- NO destructive changes. Safe to apply on existing data.

-- 1. Scheduled feature windows on FeatureFlag
ALTER TABLE `featureflag` ADD COLUMN `startsAt` DATETIME(3) NULL AFTER `lastChangedAt`;
ALTER TABLE `featureflag` ADD COLUMN `endsAt`   DATETIME(3) NULL AFTER `startsAt`;

-- 2. Multi-level referral commission configuration on ReferralCommissionRule
ALTER TABLE `referralcommissionrule` ADD COLUMN `levels`        JSON NULL AFTER `percentage`;
ALTER TABLE `referralcommissionrule` ADD COLUMN `fixedAmount`     DECIMAL(30,10) NULL AFTER `levels`;