[frewsxcv]

Summary

The app could already load and render GeoTIFF rasters from a file, but every library entry was loaded as GeoJSON because the format was hardcoded in render_add_layer_window.

• rgis-library: Entry::format() derives the format from the URL extension (.geojson / .tif / .tiff), so existing entries don't need a new field. A test makes sure every entry has a recognized extension.
• rgis-ui: AddLayerOutput::LoadFromLibrary now carries a file_format, which is passed to LoadFileMessage::FromNetwork instead of GeoJson. Entries with an unknown format get a disabled Add button.
• Two new entries under World: "Shaded Relief" (grayscale) and "Natural Earth Shaded Relief" (color).

Raster files

Both come from Natural Earth's 50m rasters (10800×5400, stored in strips). The GeoTIFF loader only reads tiled files, so I downsampled them to 4096×2048 and converted them to tiled COGs (512px blocks, no overviews):

File	Compression	Size
World/Shaded-Relief.tif	DEFLATE + predictor 2	1.6 MB
World/Natural-Earth-Shaded-Relief.tif	JPEG at quality 85 (YCbCr)	1.2 MB

Both files are already uploaded to the rgis-library bucket and can be downloaded from their public URLs.

Testing

• cargo test -p rgis-library passes.
• Both files load through geo_raster::GeoTiffSource as 4096×2048 rasters with EPSG:4326 and a full-world extent. The JPEG file's average R/G/B values match gdalinfo -stats to within 0.1, so the YCbCr colors decode correctly.
• In the native debug build, "Natural Earth Shaded Relief" loaded from the library with no errors: 250 ms to download, 1.0 s to decode (unoptimized build).
• There is no Playwright test yet for adding a raster from the library.