Logged-out tuist setup cache no longer pins a respawning daemon

tuist setup cache while logged out now fails immediately with an actionable “You must be authenticated” message and installs no LaunchAgent, instead of reporting success while installing a daemon that exits for lack of credentials. The cache-start daemon itself exits cleanly (exit 0) when not authenticated, leaving no empty session directory, and its LaunchAgent plist’s KeepAlive now uses SuccessfulExit = false, so launchd respawns only on a real crash and not on the “nothing to do” exit. With the daemon already running, logging in and out is handled per request without needing a restart.