T-1039/T-1043 in_progress + refinement appends (the locked arrangement_pattern
re-derive + RoadGraph-source decisions). Board hygiene: T-960 (Atlas map viewer)
parked since 2026-06-07 -> backlog; T-1038 (Layer 2 road graph) full scope landed
on main (c0d4ac89d) and consumed by T-1043 -> done.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>