Appends task entries to a ticket's `tasks.md` at `docs/tickets/open/{slug}/tasks.md` – the backlog the Ralph loop (`complete-tasks`) works through one fresh session at a time – creating the file on first use. Use when the user says "add tasks for docs/tickets/open/X/index.md", "break this ticket into tasks", "generate the Ralph backlog for X", or runs `/add-tasks`. The source is a ticket only. Every entry is self-contained and selectively verified, and the ticket's list ends with one full-suite gate. Strictly append-only; never edits, reorders, or implements.
