550x350 m clipped to the block, already in the project CRS, 984 KB, committed through LFS. Verified against the service's own point query and the earlier probe: 115.911/119.422/117.593 m, agreement within 6 cm. Adds Geo/scripts/dem_stats.py, a stdlib tiled-TIFF reader, because GDAL cannot run on the host and the exported raster is tiled rather than strip-organised.