Delete a workflow permanently

Deletes the workflow and everything hanging off it: its versions, its runs, their step rows, and the offloaded step payloads in object storage. There is no soft delete, no undo and no confirmation step. A published workflow is deleted without being unpublished first — its webhook URL simply stops resolving.

Deleting a workflow that another workflow references (as a Sub-flow target or an error workflow) is NOT refused; the referencing flow fails at run time instead. This route requires workflow:delete, a separate permission from workflow:write.