Scheduled prompts live at swarm level (swarm-controller's
/api/schedules, `swarmctl schedule`, the swarm UI's /schedules page).
The hive dashboard's SCH3DUL3S tab only listed the rows left in
hive-c0re's `scheduled_prompts` table so operators could copy them
over; the operator confirmed everything is migrated.
Removed:
- the SCH3DUL3S tab, its pane, schedules.js, its CSS (including the
`.rqe-source*` rules, whose only emitter was schedules.js) and the
hub tile's "schedules" entry
- hive-c0re's GET /api/schedules and the `scheduled_prompts` store
(with its v1 column migration and test)
- hive-sh4re's `schedule` wire types, which only that route used
- docs describing the tab, the route and the two tables
The rebuild-queue cancel route that shared the module moves to
dashboard/rebuild_queue.rs under an OpenAPI tag of its own.
The two sqlite tables are not dropped: nothing opens them any more,
and persistence.md says they can be dropped by hand.
Closes#4916