Implementation skeleton for exposing the eth_config JSON-RPC method (EIP-7910) as a reth Execution Extension / RPC namespace.

• Workspace layout with three crates:
  • eth-config-api: pure data model and helpers (no reth deps).
  • eth-config-reth: reth integration layer (feature-gated) with resolver/cache/RPC stubs.
  • eth-config-cli: optional CLI to diff eth_config responses across nodes.
• Example JSON payloads under examples/ that mirror the EIP response shape.
• Makefile shortcuts for fmt/lint/check/test/doc and CLI build.

• Types, module structure, and placeholder resolvers are in place.
• Integration logic still needs to derive fork data from ChainSpec, compute FORK_HASH (EIP-6122), and wire jsonrpsee modules into reth.
• Golden tests are stubbed and marked #[ignore]; they need real fixtures from the EIP.

• make fmt — format workspace.
• make lint — clippy all targets; set FEATURES=reth to include reth integration.
• make check / make test — fast correctness checks (tests currently placeholder).
• make doc — build docs without deps.
• make cli — build the validator CLI.

• tests/hoodi_prague.rs: parses Prague sample and checks presence of next fork id.
• tests/hoodi_cancun.rs: parses Cancun sample with blob schedule and no next fork.
• tests/no_future_fork.rs: ensures next/last null handling.
• tests/bpo_fork.rs: blob-parameter-only fork sample.
• Tests live in the eth-config-tests crate (workspace member) and currently validate the example fixtures deserialize correctly. Run them via make test or cargo test -p eth-config-tests.

• Adds the eth_config RPC method to surface the active fork, next/last fork, precompile set, system contracts, blob schedule, and FORK_HASH.
• Response shape (camelCase):
  • current, next, last: fork entries containing fork config (name, block, blobSchedule?, precompiles[], systemContracts[]).
  • forkId: { hash, next? } matching EIP-6122 semantics.
• Caching requirement: responses must invalidate when crossing a fork boundary.

• crates/eth-config-api/src: data models (types.rs), FORK_HASH placeholder (fork_id.rs), registries for precompiles/system contracts.
• crates/eth-config-reth/src: resolver/cache/RPC/namespace stubs (behind reth feature).
• crates/eth-config-cli/src: clap-based placeholder binary.
• tests/: integration test scaffolding for EIP sample outputs and edge cases.
• examples/: sample eth_config payloads for Cancun, Prague, and blob-parameter-only scenarios.

• Implement ForkConfigResolver to read reth::chain_spec::ChainSpec and emit ForkConfig for current/next/last at a given block/slot.
• Compute ForkId per EIP-6122 (hash over fork blocks) in fork_id.rs.
• Populate precompile/system-contract registries per fork and thread them through the resolver.
• Wire EthConfigApi into reth’s RPC builder (namespace.rs) using jsonrpsee.
• Fill the golden JSON fixtures from the EIP text and enable the ignored tests.

• The crate names contain hyphens; the Rust module imports use underscores (e.g., eth_config_api).
• The reth integration is feature-gated to avoid pulling the reth dependency unless requested.