Two first requests to GET .../singleton both missed the record; the
loser's insert hit the unique index and the route answered 500. A
unique violation from SingletonRecord now reruns the transaction once,
which finds the winner's record. TestSingleton fires six concurrent
first requests and requires 200 with the same id from each.
- cabana: config_reorder.yaml (title, nameFrom, modelClass, parentColumn,
sortColumn, maxDepth, partition) with fail-loud boot checks and the
built-in reorder toolbar button; list schema carries reorder
- GET/POST {controller}/reorder: scoped set (ListExtendQuery plus the
partition) locked FOR UPDATE, 409 reorder_stale on any set difference,
422 for duplicates, foreign parents, cycles and maxDepth, both columns
written without model hooks
- pact.AdminSingleton: GET {controller}/singleton (first or create, form
scope checked), form schema singleton, list/create/bulk/delete 404,
no config_list.yaml needed
- swag, inventories, token classes, CSRF walk, conformance cases, backend
lang reorder.stale and load_failed, reorder and singleton smoke tests, docs
