Regenerate the LedGrab icon family from a single Pillow script
(build/generate_icon.py): a rounded-square aperture traced by a
continuous RGB color-wheel stroke over a vignette canvas with a soft
chromatic bloom. 4x supersampled then downsampled per output for
crispness. Outputs 192/512 standard, 512 maskable (safe-area padded
for PWA round-crops), and a new 256 transparent-background tray
variant so the taskbar icon reads cleanly against light themes
instead of showing a dark tile.
icon.ico now embeds 16/24/32/48/64/128/256 frames sourced from the
transparent tray master, fixing the dark-square halo around the
file/taskbar icon on light Windows themes.
__main__ picks icon-tray.png for the tray and falls back to
icon-192.png when the tray asset isn't present (older bundles /
forks).
