[trunk-sim] backup: move backup index logic to backupinfo pkg#669

trunk-io[bot] merged 1 commit intomaster-trunkcrltest-issue-syncing/cockroach-fork:master-trunkfrom

stable-trunk-sim--trunk-20251201-140910crltest-issue-syncing/cockroach-fork:stable-trunk-sim--trunk-20251201-140910Copy head branch name to clipboard