Fix red develop 9d81b5dcb44a

The merge lane found `develop` red at `9d81b5dcb44a1f212edea7171feb08d97b938a0c` on its own: no queued PR merges until it is fixed. Failing (tests and gate stages): - `tests/test_tasks_routes_listing.py::test_exclude_done_keeps_the_task_the_term_names` - `api-unit-dc-test` The whole gate log: artifact `14559` on lane task 12843. Make `develop` pass its full gate again. Open a PR as usual: the merge lane merges a PR that fixes some of these and adds no failure even while `develop` is red.

Fixed red develop: test_exclude_done_keeps_the_task_the_term_names overflowed integer (sequence id ×10 on a high worker slot); named task now pinned to a fixed low id. Test file 24 passed, quick gate green. PR #7777 queued to merge lane.