feat(MED-100): update cart checkout flow and views

supabase/migrations/20250717075136_audit_cart.sql

@@ -0,0 +1,27 @@
+create table "audit"."cart_entries" (
+    "id" bigint generated by default as identity not null,
+    "account_id" text not null,
+    "cart_id" text not null,
+    "operation" text not null,
+    "variant_id" text,
+    "comment" text,
+    "created_at" timestamp with time zone not null default now(),
+    "changed_by" uuid not null
+);
+
+grant usage on schema audit to authenticated;
+grant select, insert, update, delete on table audit.cart_entries to authenticated;
+
+alter table "audit"."cart_entries" enable row level security;
+
+create policy "insert_own"
+on "audit"."cart_entries"
+as permissive
+for insert
+to authenticated
+with check (auth.uid() = changed_by);
+
+create policy "service_role_select" on "audit"."cart_entries" for select to service_role using (true);
+create policy "service_role_insert" on "audit"."cart_entries" for insert to service_role with check (true);
+create policy "service_role_update" on "audit"."cart_entries" for update to service_role using (true);
+create policy "service_role_delete" on "audit"."cart_entries" for delete to service_role using (true);