Cross-user data disclosure via shared batching map

Race condition in SvelteKit 2.38.0 through 2.60.0 allows remote authenticated users to read other users' data via query.batch. The query.batch implementation stores its payload-to-resolver map in module scope, allowing concurrent requests to deduplicate and resolve within one request context. Exploitation requires an application that uses query.batch and an authenticated attacker request to overlap with a victim request under rare timing conditions.