A backlog board and queue in the hub

The hub grows a backlog board and a per-repo queue, with every screen scoped to one active repo.

Added

A backlog board for the active repo, with issue creation and PRD publishing
A per-repo queue for tickets and epics, with a start and pause control and an outcome-based drain policy
A redesigned repo switcher, with every screen scoped to one active repo
Copy keys across terminal logs, the dashboard and the recap