c4da1d5525
The Wayland compositor service currently launches redbear-compositor, not kwin_wayland. Renamed kwin_pid→compositor_pid and updated the error message from 'kwin_wayland failed' to 'Wayland compositor failed'. Added comment documenting that redbear-compositor is the bootstrap compositor until KWin completes its build. The transition path is documented: replace 'redbear-compositor --drm' with 'kwin_wayland --drm' when KWin is runtime-ready.