feat(desktop): home app (system-only launch cap, LAUNCH_BADGE: apps+launch only), pm starts it with session (relaunch <=5); display keys F1/Alt+Tab next, F2 home, F4 close app (ROLE from launcher, terminal exempt), close returns to previous window; closed window -> app exits; shell 'name &'; launch by id; pm stack 8, storage 16 clients

crates/k-ui/src/run.rs

@@ -71,6 +71,7 @@ pub fn run<A: App>() -> ! {
                     dirty = true;
                     continue;
                 }
+                Event::Closed => syscall::exit(),
                 Event::Input(InputEvent::KeyDown(k)) => k,
                 Event::Input(_) => continue,
             };