feat: setup

[igorroncevic]

Description

This PR sets up the first version of Solver7702Delegate, an ERC-7702 delegation target for solver EOAs.

The contract lets approved auxiliary EOAs submit calls through the solver EOA. This gives solvers more nonce lanes for settlement submission while keeping the solver EOA as the address seen by downstream contracts.

What changed

• Added Solver7702Delegate.
• Added five immutable approved caller addresses set at deployment time.
• Added fallback-based call forwarding.
• Uses packed calldata: the first 20 bytes are the target address, and the rest is forwarded as calldata.
• Forwards ETH and bubbles up target return data or revert data.
• Rejects callers that are not in the approved caller list.
• Added a deploy script for Solver7702Delegate.
• Removed the starter Counter contract, script, and test.
• Updated README, Foundry, Slither, Solhint, and editor config for this contract.

Why

A solver EOA has one nonce lane, so transactions from that EOA must land in order. With ERC-7702, auxiliary EOAs can send transactions to the solver EOA and use their own nonce lanes, while calls still execute as the solver EOA.

This keeps the existing solver identity and avoids having to allowlist several EOAs or require every solver to use a smart contract account.

Out of scope

• Full test coverage. This is added in PR tests: add solver delegate coverage #3.
• More detailed docs.

Testing

Run:

just build
just lint
just slither

[gemini-code-assist]

Code Review

This pull request replaces the example Counter contract with Solver7702Delegate, an ERC-7702 delegation target that forwards calls from authorized addresses. It also updates tool configurations for Solhint, Slither, and Foundry. Feedback identifies a compilation error in the target address extraction logic and suggests using granular Slither suppressions instead of global detector exclusions to preserve security analysis depth.

[igorroncevic]

All of these are necessary:

• "func-visibility": ["error", { "ignoreConstructors": true }] -> constructor doesn't require explicit visibility modifier since Solidity 0.7
• "no-complex-fallback": "off" -> we explicitly need our fallback to be complex
• "no-inline-assembly": "off" -> we explicitly need assembly for gas efficiency

[igorroncevic]

Without this, lines can extend without wrapping.

[igorroncevic]

Explicit requirement for latest Solidity version

[igorroncevic]

I left these as private as to not increase the bytecode of the contract unnecessarily.

However, there would need to be some additional assumptions in services about this, because now we can no longer check if the caller is approved with isApprovedCaller (first iteration), but through some other means, e.g. simulating a transaction with a sender being e.g. Bob, and see if it would revert with Unauthorized.