Deleting a frozen object left a stale rendered mesh on screen until
the area re-streamed. Unfreezing right before DeleteObject clears it
immediately, matching how safe:despawn already looked to behave.
The cleanup loop ran on onClientResourceStart, but spawnedSafes is
already a fresh empty table by then, so it never actually deleted
anything. Props from before a restart stayed orphaned in the world
and got duplicated by the requestSync on start. Moved the cleanup to
onClientResourceStop, which runs while the entities are still known.
ExecuteCommand('restart ...') was restarting the whole FXServer
process in this environment instead of just the resource, so
/oixbupgrade now only downloads files and tells the admin to
restart manually.
