[family collaborator] have all three of us see the same workspace state after extract finishes

Walk the cross-cutting story scenarios that span pipeline + collaboration: three actors converging after an extract, adding a column mid-score, switching the view group mid-drag, friend-edits during a tailor, the agent-tailors-while-user-offline path, mid-tailor section adds, and the no-workspace-delete safety. These specs catch races that single-actor suites cannot see.

Proof set for User pastes URL, agent extracts in background, friend opens detail — all three see the final extracted fields