The packaging break: frontend/build/icon.png was deleted from the working
tree, so electron-builder had no Linux icon and every AppImage/deb it
emitted carried the generic Electron placeholder instead of the Keynctr
mark.
Regenerate build/icon.png from KeynectrAppIconPossibility02.jpeg rather than
resizing the old file:
- cut the white (254) JPEG background to transparent (alpha from luma),
- flatten the art to a square canvas with symmetric padding,
- keep the ink pure black (RGB 0,0,0), export 512x512 RGBA.
The 512x512 master satisfies both declared linux targets with the config
kept single (linux.icon: build/icon.png, no build/linux/ fan-out):
- AppImage: electron-builder downscales to 256 internally (>=256 required).
- deb: installs usr/share/icons/hicolor/512x512/apps/keynectr.png, matching
the generated .desktop Icon=keynectr.
Verified end to end (npm run dist green): the embedded icon is byte-identical
(md5 b3e372f7) in the AppImage hicolor set, the AppImage .DirIcon, and the
deb hicolor set, all 512x512 RGBA with real transparency.
The source JPEG (KeynectrAppIconPossibility02.jpeg) stays untracked, as does
the pre-existing hygiene leftover set. No package.json change needed: the
single build/icon.png path is already correct.
