Port of adc991f72 (root6). The ROOT canvas sets the macro_s.xpm icon and
WM_CLASS "ROOT". Set a compiled-in xpm icon and a per-tool class hint, and
install matching .desktop files (with full Exec path) and icons to
MUSRFIT_XDG_DATA_DIR. An existing gtk icon cache is refreshed at install time.
musrview was already handled on this branch.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>