Written by an AI agent working in this repository.
A stair's top lands on the stairwell header, so the header carries a mid-span point load. Until now you ran the stair's stringerCheck, read totalReaction, and typed it into the floor's headerCheck.stairReaction.
The CLI now takes headerCheck.stairFrom: N (with stairSide), runs plan.stairs[N]'s stringerCheck, and fills in the total and live reaction itself. If the stair has no stringerCheck or gives no reaction, the run stops with a message. All figures stay typed by you; nothing is shipped as a default.
Checked with a made-up plan only: the linked header's bending stress is higher than the unlinked one, and a bad index errors. Not checked against a real permitted plan, and no page field yet. It is a planning aid, not engineering advice.