Read pitch deck plan coverage.

Returns the pre-render report for the exact journey plan this deck would render right now: whether it still describes the current plan, the 0–10 score, the 7.0 gate and every reason it withheld a pass, seven dimensions, machine-checked plan defects, per-chapter notes, and priority fixes. While the latest draft edit's coverage waits to start it answers status: "queued"; a plan nobody has graded yet answers status: "missing" with the reason — NOT a 404, which would read as "no such pitch deck". This never returns the chapters. Scope: story:read.