The Qt GUI ships by default: smappy-gui and smappy-calibrate are on PATH
after a plain pip install smappy-smlm, and PySide6-Essentials, pyqtgraph
and matplotlib are base dependencies rather than extras.

Also: bead PSF calibration (single-channel and dual-colour), the Qt ROI
manager replacing the matplotlib one, and the global two-channel fitter
(fit_cspline_global).