When a catch misses the slot: using post-check registration

If a create arrives after the release window and the name is lost in the slot, do not assume it is gone. The engine's post-check registration re-checks the name afterwards and, if it has become available, registers it.

To make use of it:

1. Let the engine run its post-check pass rather than stopping the moment the primary attempt fails.
2. Understand it works best on lower-contention names — a heavily fought name is unlikely to be sitting available after the slot.

Treat post-check as a recovery mechanism that reclaims names your timing missed, not as your main catching method.