Port program_logic/atomic.v


## Summary

Port [`program_logic/atomic.v`](https://gitlab.mpi-sws.org/iris/iris/-/blob/master/iris/program_logic/atomic.v).



## Dependencies








**Rocq dependencies:**

- `proofmode/proofmode` (aggregation)
- #219
- #211
- #289
- #291
- #346