feat(node): Add Peers Script to Entrypoints

[refcell]

Summary

Adds a new add-peers.sh script that fetches public peer records from chains.base.org/<chainName>/peers and registers them with both the execution and consensus layers. Each execution entrypoint (geth, reth, nethermind) runs the script in the background with --execution-only before handing off to the binary, and each consensus entrypoint (op-node, base-consensus) does the same with --consensus-only. The script loops every 300 seconds so peers are continuously refreshed. For reth, peer fetching is gated on the optional RETH_NETWORK env var since RETH_CHAIN may be a file path rather than a human-readable chain name.

[cb-heimdall]

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