feat: add admin accounts and image templates

supabase/schema.sql

@@ -82,6 +82,19 @@ create table if not exists projects (
   updated_at timestamptz not null default now()
 );
 
+create table if not exists image_templates (
+  id text primary key,
+  owner_id text not null,
+  name text not null,
+  description text,
+  prompt text not null,
+  preview_image_url text,
+  settings jsonb not null default '{}'::jsonb,
+  sort_order integer not null default 0,
+  created_at timestamptz not null default now(),
+  updated_at timestamptz not null default now()
+);
+
 create index if not exists assets_owner_created_idx on assets(owner_id, created_at desc);
 create index if not exists generation_jobs_owner_created_idx on generation_jobs(owner_id, created_at desc);
 create index if not exists generation_jobs_status_idx on generation_jobs(status);
@@ -91,6 +104,7 @@ create unique index if not exists generation_jobs_idempotency_idx
   on generation_jobs(owner_id, external_client_id, idempotency_key)
   where external_client_id is not null and idempotency_key is not null;
 create index if not exists usage_events_owner_created_idx on usage_events(owner_id, created_at desc);
+create index if not exists image_templates_owner_sort_idx on image_templates(owner_id, sort_order asc, updated_at desc);
 
 create or replace function claim_generation_jobs(
   p_worker_id text,