feat: add platform staff management

supabase/migrations/202606300006_platform_staff_status.sql

@@ -0,0 +1,18 @@
+alter table public.platform_users
+  add column if not exists status text not null default 'active';
+
+do $$
+begin
+  if not exists (select 1 from pg_constraint where conname = 'platform_users_status_check') then
+    alter table public.platform_users
+      add constraint platform_users_status_check
+      check (status in ('active', 'disabled'));
+  end if;
+end $$;
+
+update public.platform_users
+set status = 'active'
+where status is null;
+
+create index if not exists idx_platform_users_role_status
+  on public.platform_users(primary_role, status, created_at desc);