Replace the worker retry/ignore-list claim-loop with a single atomic
SELECT ... FOR UPDATE SKIP LOCKED claim (SQLite bounded-retry fallback),
preserving the no-duplicate guarantee while removing the thundering-herd
contention that throttled backlog draining. Add a (status,type,last_updated)
index via the table-creating migration + db:add-missing-indices listener.
Signed-off-by: Yoan Bozhilov <bygadd@gmail.com>
Assisted-by: Claude Code:claude-opus-4-8
