Icons, app icon and splash drawn in code

Makes every icon and every piece of brand art in an Expo app come from code: UI icons are layers on a 24-unit grid flattened into one Skia path each and shown by <Icon> as tinted native images; one brand mark (layer data in theme colour roles) draws the in-app tile, the iOS light, dark and tinted icons, the Android adaptive and themed layers, the splash and the Play icon. Two checkers prove the icon set, the source bans, the rendered PNGs against each platform's rules, the config wiring and the mark.

Rules that must hold