Warden monochrome assets

Use the supplied existing W contour without changing its proportions.
Black (#111214) is for light surfaces; warm white (#F4F3ED) is for dark surfaces.
Symbol SVGs and PNGs have transparent backgrounds. Square icon files include their intended light or dark background and generous padding; the maskable icon keeps the mark in the central safe area.
The current lime iOS app icon is preserved separately in ../lime/.
No font files are included. Wordmark lettering is outlined for portable rendering.
See ../warden-design.md for the complete file guide.
