geo: sample seven cross-sections from the DEM

Gutters sit at -10 m south and +10..12 m north, a ~2% crown between them, and
the envelope runs 0.6-1.0 m per section. Gutter spacing independently confirms
the 20.9 m carriageway measured from the crossing. The sharpest breaks are
0.09-0.12 m/m, so 3DEP does not resolve a kerb upstand: kerb height stays a
recorded assumption rather than a derived value.

Geo/verification/2026-11-06-elevation.md

@@ -52,5 +52,5 @@ Window statistics: min 110.46 m, max 127.73 m, spread 17.28 m — building tops
 
 ## Next
 
-1. Sample the kerb line and the crossing ramps specifically — the grid above is a street-level average, not a kerb profile.
+1. ~~Sample the kerb line and the crossing ramps~~ — done: seven cross-sections in [`2026-11-06-cross-sections.md`](2026-11-06-cross-sections.md) locate the gutters at ±10–11 m and show a ~2 % crown. They also show the DEM does **not** resolve a kerb upstand, so kerb height stays an assumption.
 2. Build the ground mesh from the DEM along the street, not from a flat plane, and assert the 3.94 m fall survives the Blender→Unreal path.