Replace the default Godot boot splash and exe icon with the RanaZe
mark so a Windows build reads as RanaZe from first launch, not the
engine it's built on.
Replaces the OS/window icon with the new dark-background logo design,
and derives a transparent shield-mark cutout (via chroma-key against
the flat background) for the in-app login/sidebar mark and the web
loading-screen logo. Brand.ranaze_mark_texture() no longer needs the
AtlasTexture crop since the new source asset is already tightly
cropped to the mark.
hz