Audit and remove stale EVM integration code

[Dominik1999]

Summary

There is EVM integration code in the repository. We should evaluate whether it is still needed.

Questions

• Is any EVM chain currently using the Guardian?
• If not, the EVM code should be removed

Broader scope

Beyond EVM, do a general audit for any other stale or unused code in the repository. The goal is to keep the codebase clean and maintainable.

[zeljkoX]

Thanks for creating the issue.

Long term we should definitely evaluate how to best support multiple networks.

At the moment EVM support is already behind an opt-in Cargo feature gate (crates/server/Cargo.toml:71: evm = ["alloy"], not in default), and all EVM code paths in the server are wrapped in #[cfg(feature = "evm")]. Default builds pull in zero EVM dependencies and ship effectively no EVM code, so the maintenance cost today is minimal.