feat: centralize MTU constants and fragmentation logic#503

PeterGRutherford wants to merge 5 commits intodevelopmentSOVEREIGN-NET/The-Sovereign-Network:developmentfrom

fix/standardize-mtu-handling-across-protocolsSOVEREIGN-NET/The-Sovereign-Network:fix/standardize-mtu-handling-across-protocolsCopy head branch name to clipboard