feat(op-node): chain replication via BOP_REPLAY env

[thedevbirb]

The following PR introduces some lookup checks on the environment variable BOP_REPLAY to assess whether this follower node is running in chain replication mode or not.

Chain replication consists of replaying past L2 blocks of the chain but at the current time, which is something op-node hasn't been really designed for. As such, this env disable some important checks and routine usually used in production:

1. Any check related to timestamps being too old: both when validating incoming blocks and sending sync requests, those actions are rejected if the block timestamp is older than 60s compared to current unix time.
2. Derivation pipeline, and other L1-driven sync behaviour: this allows to run chain replication using a synced L1 node and without worrying about having also L1 nodes pinned at some past block in time. Doing so requires however disabling checks that would make the chain change because of new data of the target chain we're replaying.

The result is a follower node which is able to ingest past L2 blocks and process them unsafely (because of the two points above).

There are some past commits where I tried to use a CLI flag instead, but imo they end up in more diffs and injecting this testing configuration in structs etc which is not desiderable. I kept them for reference, but I can squash everything in one commit if desired.

[ltitanb]

looks good! a lot of changes seems to be formatting, not sure if there's an equivalent of just fmt (of it it was not set). If not then happy to merge with the formatting changes too

[ltitanb]

could we refactor this to a small function we call instead? also assuming this does a syscall every time it's called so if on the hot path maybe we could use a global static / atomic instead? if not then ok to keep this

[thedevbirb]

Right, a static is probably simpler in this case. Btw os.LookupEnv doesn't make a syscall but calls this https://cs.opensource.google/go/go/+/refs/tags/go1.25.1:src/syscall/env_unix.go;l=66 and it is all in memory.

Pushing a change soon!

[thedevbirb]

See 86fd3cc.

Regarding formatting, I don't see some tooling specifically used for it, this is what my LSP with go fmt did. But I can rollback individual changes if you want.