-- 0026_users_timezone.up.sql — per-user timezone for the system-playlist
-- scheduler (#392 Half B). Default 'UTC' so existing rows + brand-new
-- users have a safe value before their first client check-in via
-- PUT /api/me/timezone. The scheduler reads this column to decide
-- which IANA zone to anchor each user's daily 03:00 build to.
ALTER TABLE users
    ADD COLUMN timezone text NOT NULL DEFAULT 'UTC',
    ADD COLUMN timezone_updated_at timestamptz;