FX.67 Wall Length and typed dimension: no choice of fixed end, no marker for the fixed side, no modifier-key drag to break a join

Wall tool spec pages 11-12 (Duncan, 2026-11-05), tracked at /roadmap-internal 'BimCraft wall tool specification'. Checked in the a Discord member source 2026-11-05. Page 11 'BimCraft must' column, three things the code does not do: (1) Changing length: 'start end fixed by default; toggle to grow from the other end or the centre'. setLength (wall-square.js) always keeps the start end and moves the end; there is no toggle. (2) Typing a dimension value: 'a marker shows the fixed side before Enter'. No marker exists; the fixed side is not shown. (3) Breaking a join: 'only by Split, Disallow join, delete, or a modifier-key drag'. No modifier-key drag breaks a join (Split and Disallow join are WT.4 and WT.5). Wanted: a Grow from control on the Length field (start | end | centre) with the fixed side drawn on the plan while the field is focused, and a modifier-key drag (Revit's Move with Disjoin) that moves a wall without carrying its joins and keeps the wall's id. Spec tests 3 and 9. OTHER APPS: CadCraft plan walls have no Length field or toggle either (FX.59). Not started.

walls-09 2026-11-06: Built in /lab: Properties › Grow from (Start holds | End holds | Centre holds) next to Length; the side that holds is marked on the plan while the Length field is in use; Alt + drag of the middle grip moves the wall free of its joins (they break, the id stays). Tests: --walltools (grow from end and centre, marker point), browser-walltools (grow from end, marker, Alt-drag).