This package reproduces the minimumGasLimit fork-activation halt against the reference Optimism commit:
559c958d0746670420398195bd605c5c2055f02f
The live reproduction uses the in-process op-e2e/actions cluster: a real L1 miner, L1 receipts, the op-node derivation pipeline, and an op-geth L2 engine. It does not rely only on arithmetic or mocks.