Adds a view-refresh icon button in the top-right corner to re-fetch the
Steam library. A countdown label appears below it during the cooldown and
hides when the timer expires, preventing API spam.
- Set QT_QPA_PLATFORM=wayland when WAYLAND_DISPLAY is present so the
app runs natively instead of via XWayland
- Show version string (v0.1.0-<git short hash>) in bottom-left corner
