FX.59 CadCraft 2D plan walls: joins are found by position at each edit, not stored; same edit rules as BimCraft wanted

Wall tool spec (Duncan, 2026-11-05), tracked at /roadmap-internal 'BimCraft wall tool specification'. Assessed 2026-11-05 as part of FX.57. CadCraft's plan walls (lib/plan2d/walls.js, used by app/walls-cmd.js) have their own engine. followMoves already carries a wall joined end to end and slides a T end along its own line, which is more than BimCraft's Move does. But joins are still guessed from end positions each time (no join record), there is no Disallow join or Split that keeps joins, and a typed length or a thickness change has not been checked against the five rules (joined walls follow and stay joined, selected wall moves and the reference holds, location line holds, one undo step, Length and dimension name their reference). Wanted: run the spec's nine tests (they are plan-view, they apply as written) against CadCraft, fix what fails, and share the join record with FX.60. Not tried yet; nothing changed.

Page 3 check (2026-11-05): followMoves puts a shared end at the moved end and leaves the far end, so a neighbour turns when a wall is moved sideways (finding 2 applies here too: FX.63); T ends already slide (finding 3 does not apply). Move already follows joins (finding 1 does not apply).

walls-plan-09 2026-11-06 (done): Built in /lab: CadCraft plan walls store their joins. Each wall has its own id and the join records (end meets start, end meets mid for a T, mid meets mid for a crossing: the same record as BimCraft, rules in lib/walls/joins.js, checked equal to BimCraft's wall-joins.js); both walls carry it, in the... see docs/0.9-sessions/walls-plan-09.md.