Replace the localStorage kanban with the backend-backed board, add typed clients
and a React hook with optimistic updates. Cards can reference static doc pages
and user-created custom pages (new "custom" reference type with purple chips).
Add the agentic orchestrator UI: a per-card panel to launch `pi` runs, watch a
live tool/thought stream over SSE, steer mid-run, and stop — while the board
stays fully interactive. The board page wires the orchestrator and custom-pages
stores into every card.