GHSA-5qfp-32cf-69jh: SurrealDB: HTTP /rpc `sessions` method leaks attached session UUIDs, enabling full session hijack by anonymous callers

The HTTP /rpc sessions method returned every attached session UUID without authentication, and the /rpc handler accepted an arbitrary session field with no ownership check. An anonymous caller could enumerate UUIDs and impersonate any authenticated session.

“Attached” means sessions registered via {"method":"attach"} — the only writer to the HTTP session map. Ordinary stateless /rpc requests use ephemeral per-request sessions that are filtered from sessions() and destroyed at end-of-request, so they are not enumerable.