Electron's desktop-half reconcile (reconcileUnifiedDesktopHalves) only
walks this machine's hermes homes, so a unified package installed on a
remote backend can never materialize into the app's desktop-plugins
root. The renderer still derived desktopMissing from the backend's
has_desktop_half, painting an eternal 'copying…' state that reads as a
transfer in progress (#114079).
Show an honest 'unavailable (remote backend)' state (with an explanatory
tip) whenever the live resolved connection mode is remote; keep the
pending state for local backends, where the reconcile really can catch
up on rescan or restart.
Fixes#114079
(cherry picked from commit 2e35b47495c699b619f9899da988dea24f2b6632)
2bc2c50df3