feat: add l2 fork testing framework #1582

Job	Run time
detect-changes	48s
prep	57s
build-fork (op-deployer) / safety-checklist	9s
build	0s
build-fork (op-deployer) / build (linux/amd64, ubuntu-latest)	2m 56s
build-fork (op-deployer) / build (linux/arm64, ubuntu-24.04-arm)	3m 24s
build-fork (op-deployer) / merge multi-arch manifest	20s
check-cross-platform (op-deployer, ubuntu-24.04-arm)	10s
check-cross-platform (op-deployer, ubuntu-24.04)	5s
build-fork (op-deployer) / attest build provenance	-1s
check-cross-platform-rust	0s
docker-build-result	2s
	8m 50s

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