-- Tables affected: qt_configurations
-- recovery.not-started: check first; ADD COLUMN fails if owner_username already exists
-- recovery.partial: ALTER TABLE qt_configurations DROP COLUMN owner_username;
-- recovery.completed: no action needed
-- verify: owner_username column missing | SELECT 1 FROM information_schema.COLUMNS WHERE table_schema=DATABASE() AND table_name='qt_configurations' AND column_name='owner_username' HAVING COUNT(*)=0

-- Store configuration owner as username (instead of relying on numeric user_id)
ALTER TABLE qt_configurations
    ADD COLUMN owner_username VARCHAR(100) NOT NULL DEFAULT '' AFTER user_id,
    ADD INDEX idx_qt_configurations_owner_username (owner_username);

-- Backfill owner_username from qt_users for existing rows
UPDATE qt_configurations c
LEFT JOIN qt_users u ON u.id = c.user_id
SET c.owner_username = COALESCE(u.username, c.owner_username)
WHERE c.owner_username = '';