Fix devnet genesis gasLimit mismatch and RPC test chain ID validation

[Copilot]

Devnet's block gas capacity was misconfigured at 8M while feeConfig.gasLimit and mainnet/testnet are all set to 20M, causing behavioral divergence. The test_chain_id RPC test was also broken: it passed the chain ID as the JSON-RPC request id, omitted params, and only printed results — meaning the test could never fail.

Changes

• chains/devnet/genesis.json: Correct top-level gasLimit from 0x7a1200 (8M) → 0x1312D00 (20M) to match config.feeConfig.gasLimit and align with mainnet/testnet

• rpc/rpc_test.py: Fix test_chain_id to use a proper JSON-RPC payload and assert the response:

  # Before: chain_id used as request id, no params, only prints
  def test_chain_id(rpc_url, chain_id):
      payload = {"jsonrpc": "2.0", "method": "eth_chainId", "id": chain_id}
      ...
      print("RPC request successful, Response Data:", response_data)
  
  # After: correct payload, actual assertion
  def test_chain_id(rpc_url, expected_chain_id):
      payload = {"jsonrpc": "2.0", "method": "eth_chainId", "params": [], "id": 1}
      ...
      actual_chain_id = int(response_data["result"], 16)
      assert actual_chain_id == expected_chain_id, \
          f"Chain ID mismatch: expected {expected_chain_id}, got {actual_chain_id}"

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Feature][High] Fix devnet genesis gasLimit mismatch and RPC test chain ID validation bug</issue_title>
<issue_description>## Summary

Two correctness bugs that affect development and testing reliability.

Findings

1. Devnet genesis gasLimit mismatch (Configuration Bug)

File: chains/devnet/genesis.json, lines 5 and 47

The devnet genesis has a critical inconsistency:

• config.feeConfig.gasLimit = 20000000 (20M)
• Top-level gasLimit = "0x7a1200" = 8000000 (8M)

On mainnet and testnet, these are aligned at 20M / "0x1312D00". This mismatch means transactions that succeed on testnet/mainnet may fail on devnet due to different block gas capacity, defeating its purpose as a pre-production environment.

Fix: Change line 47 from "gasLimit": "0x7a1200" to "gasLimit": "0x1312D00".

2. RPC test chain_id validation bug (Logic Bug)

File: rpc/rpc_test.py, lines 40-52

The test_chain_id function has a bug: it passes the expected chain_id value (e.g., 10507) as the JSON-RPC "id" field instead of using it to validate the response. The function also omits the required "params": [] field. Most critically, none of the test functions actually assert returned values -- they only print, meaning tests can never fail.

Fix:

def test_chain_id(rpc_url, expected_chain_id):
    payload = {
        "jsonrpc": "2.0",
        "method": "eth_chainId",
        "params": [],
        "id": 1,
    }
    response = requests.post(rpc_url, json=payload)
    response_data = response.json()
    actual_chain_id = int(response_data["result"], 16)
    assert actual_chain_id == expected_chain_id, \
        f"Chain ID mismatch: expected {expected_chain_id}, got {actual_chain_id}"

Impact

• Devnet testing does not accurately reflect production gas behavior
• RPC tests provide false confidence as they never fail regardless of actual results

Generated by Health Monitor with Omni</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Feature][High] Fix devnet genesis gasLimit mismatch and RPC test chain ID validation bug #120

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