foundry: determinstic bindings with bytecode hash

The solidity compiler appends an IPFS hash of the metadata and the compiler version at the end of the bytecode.

https://docs.soliditylang.org/en/latest/metadata.html#encoding-of-the-metadata-hash-in-the-bytecode

At the moment despite the metadata being the same (can be checked by running `forge build --extra-output-files metadata --force` and finding the metadata files in `contracts/out`) the IPFS hash is sometimes different. This is very troublesome because we want to generate consistent bindings on all our dev machines and the CI.

It may be possible to disable this metadata hash but that's not desirable. Currently waiting for foundry community to see if they have any suggestions about how to further debug this.

Another maybe related problem is differences in bindings (not just due to bytecode differences) in the CI vs locally.

cc @alxiong

Start by running `forge build --extra-output-files metadata --force` and comparing the metadata files under `contracts/out` across local and CI environments. Trace how bytecode hashes and bindings are generated, using the Solidity metadata documentation linked in the issue as context. Done means the cause of differing hashes or bindings is identified and deterministic generation is restored or clearly scoped.

Written by the indexing model from the issue text.