fix(deps): update ruint security advisory

[PelleKrab]

Summary

• update ruint from 1.17.2 to 1.20.0 to resolve RUSTSEC-2026-0220
• remove the stale RUSTSEC-2025-0141 ignore now that bincode is no longer in the dependency graph
• restore cargo deny check on the current advisory database

Why

The proof API PR stack exposed a pre-existing time-dependent CI failure: cargo-deny rejects ignored advisories that are no longer encountered. A fresh advisory fetch also reports the newly published ruint shift-overflow advisory, which is fixed by the compatible 1.20.0 release rather than suppressed.

Lockfile scope

The lockfile contains only the dependency graph required by ruint 1.20.0: six new ark-* 0.6.0 packages and version qualification of the existing ark-serialize 0.5.0 edge because both 0.5 and 0.6 now exist. It does not change any unrelated Windows dependency resolution.

This is the prerequisite for the proof API stack:

1. this PR — dependency/advisory maintenance
2. feat(anvil): add Base proof devnet L1 APIs #67 — upstream debug endpoint cherry-picks + Beacon /eth/v1/config/spec

Validation

• cargo metadata --locked --no-deps --format-version 1
• cargo deny check
• cargo check -p anvil --locked
• cargo test -p anvil --test it beacon_api --locked -- --nocapture
• git diff --check