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/README.md

@@ -13,7 +13,7 @@ OSM is layout data only. It is not authoritative for façade detail, height, or
 | `Geo/manifests/` | One manifest per saved extract (see below) |
 | `Geo/scripts/` | Repeatable fetch and conversion helpers |
 
-Current state: the extract, both El Capitan footprints, the demo bounds, the building sets, the street profile, and the designated crossing are recorded in [`verification/`](verification/). The local CRS and origin are fixed in [`manifests/local-origin.md`](manifests/local-origin.md), with the projected easting/northing still to be computed. Elevation is measured and the 3DEP 1 m DEM window is committed (EPSG:26911, NAVD88, 984 KB). The hero façade width remains open.
+Current state: the extract, both El Capitan footprints, the demo bounds, the building sets, the street profile, and the designated crossing are recorded in [`verification/`](verification/). The local CRS and origin are fixed in [`manifests/local-origin.md`](manifests/local-origin.md), with the projected easting/northing still to be computed. Elevation is measured and the 3DEP 1 m DEM window is committed (EPSG:26911, NAVD88, 984 KB). The street cross-sections (crown ~2 %, gutters at ±10–11 m) are in `verification/`. The hero façade width remains open.
 
 ## Required manifest