CREATE TABLE IF NOT EXISTS ad_channels (
  id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
  name text NOT NULL,
  url text,
  status text NOT NULL DEFAULT 'active' CHECK (status IN ('active','paused')),
  memo text,
  created_at timestamptz NOT NULL DEFAULT now(),
  updated_at timestamptz NOT NULL DEFAULT now()
);

ALTER TABLE ad_channels ENABLE ROW LEVEL SECURITY;
-- service_role(관리자 API)만 접근 — 별도 policy 없음(기본 거부)