Use Nethermind Kademlia package in libp2p

[flcl42]

Summary

This replaces the copied Kad-DHT Kademlia core in libp2p with the shared Nethermind.Kademlia package built from current Nethermind master.

The libp2p-specific peer, key, storage, transport, and session adapters stay in this repository, while the generic routing table and lookup implementation move behind the package dependency.

Details

• Adds repo-local package artifacts and NuGet sources so locked restores can resolve the rebuilt Kademlia dependency.
• Updates Kad-DHT integration code to use the current Nethermind Kademlia API, including the lookup streaming surface.
• Keeps the Kad-DHT project MIT-licensed and documents the separate LGPL package dependency.
• Updates the transport-interop lock file for the refreshed dependency graph.
• Keeps Windows solution builds from targeting MAUI Apple platforms while still allowing those targets on macOS.

Validation completed locally.