Shrink the txmgr seam. Since the batcher builds the txmgr config itself, it can capture the ChainSigner right there — then op-service/txmgr/espresso.go (the new SimpleTxManager.Sign/SignTransaction methods) and the runtime type assertion in initChainSigner can be deleted, and txmgr's public API stays identical to upstream, which matters for our rebases. Related: ChainSignerFactoryFromConfig is a near-verbatim copy of SignerFactoryFromConfig, which now has no production callers — we should keep exactly one factory.
Original discussion: #459 (comment)
Shrink the txmgr seam. Since the batcher builds the txmgr config itself, it can capture the
ChainSignerright there — thenop-service/txmgr/espresso.go(the newSimpleTxManager.Sign/SignTransactionmethods) and the runtime type assertion ininitChainSignercan be deleted, and txmgr's public API stays identical to upstream, which matters for our rebases. Related:ChainSignerFactoryFromConfigis a near-verbatim copy ofSignerFactoryFromConfig, which now has no production callers — we should keep exactly one factory.Original discussion: #459 (comment)