feat: render question exports as assets

supabase/migrations/202606290018_content_export_binary_worker.sql

@@ -0,0 +1,40 @@
+alter table public.content_export_jobs
+  drop constraint if exists content_export_jobs_format_check,
+  drop constraint if exists content_export_jobs_status_check;
+
+alter table public.content_export_jobs
+  add constraint content_export_jobs_format_check
+  check (format in ('json', 'paper_json', 'print_payload', 'pdf', 'docx'));
+
+alter table public.content_export_jobs
+  add constraint content_export_jobs_status_check
+  check (status in ('pending', 'rendering', 'completed', 'failed'));
+
+alter table public.content_export_jobs
+  alter column status set default 'pending';
+
+alter table public.content_export_jobs
+  add column if not exists asset_id uuid references public.content_assets(id) on delete set null,
+  add column if not exists locked_at timestamptz,
+  add column if not exists locked_by text,
+  add column if not exists attempt_count integer not null default 0,
+  add column if not exists max_attempts integer not null default 3,
+  add column if not exists next_attempt_at timestamptz,
+  add column if not exists started_at timestamptz;
+
+do $$
+begin
+  if not exists (select 1 from pg_constraint where conname = 'content_export_jobs_attempt_count_check') then
+    alter table public.content_export_jobs
+      add constraint content_export_jobs_attempt_count_check
+      check (attempt_count >= 0 and max_attempts > 0 and attempt_count <= max_attempts);
+  end if;
+end $$;
+
+create index if not exists idx_content_export_jobs_worker_queue
+  on public.content_export_jobs(status, next_attempt_at, created_at)
+  where status = 'pending';
+
+create index if not exists idx_content_export_jobs_asset
+  on public.content_export_jobs(tenant_id, asset_id)
+  where asset_id is not null;