Each check starts two gdbus processes (about 5.5 ms of CPU each on the
Frame), so checking once a second cost about 1% of a core for as long as
the desktop ran. On SteamOS 0.3.0 native activation fails, so the watcher
always runs. A registry left behind now goes within 5 seconds instead of 1.
design.md also says where the watcher matters: started from the VR
launcher, the desktop runs in steam.service, which doesn't stop with it,
so keep-apps.sh and the unit's stop don't clean up there.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>