build_skeleton.py sweeps the confirmed standard section (R6982 inner, 300 mm
lining, R7402 excavation, crown 6.615 m above road) along the centreline for
4+745..5+480, road = 계획고, ground = 지반고 band. Walls and invert are
approximations and recorded in meta. Verified: inner radius identity, crown
height, chord length 799.9 m for 4+700..5+500. Viewer uses three.js 0.160.0.
Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01A5Cun3RHQKna9qxE6ybZ4A
