Bug Fix: ScheduleManager::start() held mutex_ and then called loadCache(), which re-locks the same non-recursive mutex. Whenever a schedule cache file was present (the normal state for a provisioned kiosk), this self-deadlocked and blocked SDL_AppInit before the first frame was presented, so the kiosk booted to a black screen showing only the compositor cursor.
Narrow the lock scope so loadCache() acquires mutex_ itself, and add a regression test that starts with a cached payload present.
NeilClack