Migrate local forks to Anvil

[clement-ux]

Plain-English summary

After #2998, operational commands no longer need Hardhat. One active Hardhat job remains: starting a local blockchain or a fork of a live network for development and simulation.

This PR replaces that node with Anvil. The previous Hardhat node is kept temporarily as a comparison tool so we can generate the same Safe transaction with both implementations and compare the important fields before deleting Hardhat.

Before and after

Before: scripts/tests → Hardhat node → forked network
After:  scripts/tests → Anvil       → forked network

For Safe batches, both paths are run and compared on:

• chainId
• to
• value
• data

Gas estimates and metadata are intentionally ignored because they are node-specific and do not change the transaction's meaning.

What changes in this PR

• make Anvil the canonical local/forked node for mainnet, Arbitrum, Base, Sonic, Plume, Hoodi, and HyperEVM;
• connect Brownie to external Anvil networks;
• migrate impersonation, balance, and code-mutation calls to anvil_* RPC methods;
• preserve the previous node wrapper as hardhat-node.sh for temporary A/B comparison;
• add the Safe batch comparator;
• add Anvil, Brownie bridge, and Safe payload comparison tests.

What does not change yet

• the standalone ops CLI introduced in Introduce standalone ops CLI #2998 is unchanged;
• Hardhat packages and configuration remain only to run the temporary legacy node;
• Hardhat is deleted in Remove the Hardhat runtime #3000 after this replacement layer is reviewable on its own.

Stack and merge order

Base: #2998 (chore/introduce-standalone-ops-cli)

1. Remove obsolete historical scripts and artifacts #2997 — remove obsolete historical scripts and artifacts
2. Introduce standalone ops CLI #2998 — introduce standalone ops CLI
3. Migrate local forks to Anvil #2999 — migrate local forks to Anvil (this PR)
4. Remove the Hardhat runtime #3000 — remove the Hardhat runtime

Merge in cascade: #3000 → #2999 → #2998 → #2997 → master.

What to review

Please focus on node and simulation parity:

• does each supported network use the correct chain ID and fork configuration?
• are impersonation, balance changes, and code changes translated to the correct Anvil RPC methods?
• does Brownie connect to the external node correctly?
• does the Safe comparator check all fields that determine transaction meaning?

Validation

• pnpm test:tasks — 38 passing
• pnpm test:anvil — 3 passing
• pnpm test:brownie — 4 passing
• pnpm test:scripts — 66 passing
• pnpm test:layouts — 11 passing
• pnpm typecheck
• pnpm lint:js, pnpm lint:ts, pnpm prettier:check
• full GitHub CI passes