fix: Implement nonce manager with reorg protection

[ledgerpilot]

Closes #3

What changed

This fix implements a thread-safe NonceManager for agents to acquire and confirm transaction nonces, featuring automatic synchronization with on-chain state and robust reorg protection with transaction re-queueing capabilities.

Files modified

• switchboard/nonce_manager.py
• tests/test_nonce_manager.py

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Draft PR — please review before merging.

[abhicris]

Merged 🎉 Correct paradigm — nonce management is a client-side concern (the chain itself owns nonces, you just need a local cache + reorg detection). The thread-safe design with ChainClient protocol is clean.

You're now a kcolbchain Contributor. Your switchboard work, combined with the meridian PRs, makes you our most prolific contributor this week. DM me on Twitter (@kcolbchainX) — want to talk about more substantial work.

— Abhishek