feat/ours-citus/stop: OURS on Citus lane closed 2026-10-02. Backup CronJob citus-backup (G1), cleanup (G2), partitioning of domain trust and host-lifecycle membership (G3; ours-api 1.4.318, migrations 0173-0176). Record: ours-and-yoars-main docs/lanes/lane_ours_citus.md and stop commit 7f0df538. No start tag was set; this tag marks the state at close.