The shell now reads snapshot.appearance.wallpaper and feeds the domain
WallpaperTheme directly into render_wallpaper. The chrome enum is
deleted; the four design themes (Dawn / Violet / Mint / Slate) all map
to base + upper-blob + lower-blob HSLA palettes that approximate the
design's radial gradients with GPUI's 2-stop linear gradient pair.
Switching themes via core.set_wallpaper_theme now propagates through
snapshots into the next render.
ZacharyZhang-NY
9780fdbc8c