The stable channel compares versions; the testing channel offers the staging
build of another commit. The channel switch is the starter's only, not the
simulator's.
The 146px right margin pushed the version and social icons inwards on every
window width. Padding the whole bar down by the caption height gives the OS
buttons a strip of their own and leaves the cluster where it was; the strip
drags the window, so the handler moves to the bar's border.
Scenery parsing runs on Parallel.ForEach and the reload button does it off
the UI thread. The splash window only appears when loading passes 300ms, so
a warm start goes straight to the main window. The log button moves into the
navigation row, dropping the separate caption strip; timetable and info use
the shared MonoFont family instead of a hard-coded Consolas.
Use the Starter icon for the window and the executable; the whole caption strip drags the window. Extending the client area makes Avalonia 12 add an extra full-screen toggle to the window chrome (which lives in its own host, so it is not reachable from the window's visual tree); it is hidden globally in App.axaml via its WindowDecorationProperties.ElementRole. Standard minimize / maximize / close are kept.
#16 and #12 Start is enabled only with crew/passenger (hold Ctrl to force); the chosen starting vehicle is carried through launch; loading-screen logo; help menu; runtime language picker.
