fix: publish FWSS library ABIs

[rvagg]

Rails library in particular has event signatures, and I've just discovered that we don't have these published ABI artifacts. I guess we've missed the 1.3.0 boat but we should remember for next time - any non-empty library we extract should have ABI artifcats included.

[Copilot]

Pull request overview

This PR ensures ABI artifacts are published not only for core FWSS contracts, but also for non-empty first-party libraries (notably Rails, which defines event signatures consumed externally).

Changes:

• Updates make update-abi to rebuild from a clean Foundry build and (intended to) discover non-empty ABIs for libraries under src/lib/.
• Documents that consumers should include Rails.abi.json in addition to the main FWSS ABI to subscribe to proxy-emitted events.
• Adds checked-in ABI JSON artifacts for Rails and SignatureVerificationLib.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
service_contracts/README.md	Updates ABI management docs to include library ABIs and event-consumer guidance.
service_contracts/Makefile	Reworks update-abi to regenerate ABIs from a clean build and attempt library ABI discovery from artifacts.
service_contracts/abi/SignatureVerificationLib.abi.json	Adds published ABI artifact for the signature helper library.
service_contracts/abi/Rails.abi.json	Adds published ABI artifact for Rails-emitted FWSS proxy events.

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[wjmelements]

This creates a separate abi.json for the libraries but ideally we would want the events from those libraries included in the ABI of the implementation that links them. This is because web3 libraries reading ABI will assume the events were emitted from the contract address with the ABI, but libraries are accessed via DELEGATECALL. So we want to merge library events into the abi.json of the contracts that use them, and discard other library fields such as their method ABI, which are useless externally.

We could keep them separate like this but then the merging would need to happen in all of the consumers. I think it best we merge the ABIs in one place.

A similar problem occurs with proxy ABI; what these have in common is DELEGATECALL.