Avoid unauthenticated Engine API probe in consensus-entrypoint

[riyue121]

Summary

This PR updates the consensus-entrypoint readiness check to avoid probing the execution client's Engine/Auth RPC endpoint without JWT authentication.

Previously, the script used:

curl "${BASE_NODE_L2_ENGINE_RPC/ws/http}"

When BASE_NODE_L2_ENGINE_RPC=ws://execution:8551, this expands to:

http://execution:8551

This sends an unauthenticated request to the Engine/Auth RPC endpoint. base-reth-node correctly returns 401, but it also logs the request as an error:

Invalid JWT: Authorization header is missing or invalid

This is a false positive and can be confusing during node operations and debugging.

Change

Instead of probing the Engine/Auth RPC endpoint, this PR checks the regular execution JSON-RPC endpoint using eth_chainId:

curl -s --max-time 10 --connect-timeout 5 \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","method":"eth_chainId","params":[],"id":1}' \
  http://execution:8545 | grep -q '"result":"0x2105"'
Motivation

This avoids generating misleading Invalid JWT errors in the execution logs while still ensuring that the execution client RPC is ready before starting base-consensus.

[cb-heimdall]

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