create table if not exists public.seedream_layer_compositions (
  job_id text primary key references public.generation_jobs(id) on delete cascade,
  owner_id text not null,
  base_asset_id text not null,
  base_visible boolean not null default true,
  layers jsonb not null default '[]'::jsonb,
  version bigint not null default 1 check (version > 0),
  created_at timestamptz not null default now(),
  updated_at timestamptz not null default now(),
  constraint seedream_layer_compositions_layers_array_check check (jsonb_typeof(layers) = 'array')
);

create index if not exists seedream_layer_compositions_owner_updated_idx
  on public.seedream_layer_compositions(owner_id, updated_at desc);