Lodestar v1.46.0 Fixes Hangs, Adds Fork Prep

Lodestar v1.46.0 released—recommended upgrade for mainnet/testnet. Fixes shutdown/restart hang bugs, smoother sync. Refuses block production on optimistic heads; skips sync-committee signing while optimistic. Removes Bun support; Node ^24.13.0 required. Docker/binary operators need no migration. Adds Gloas/Heze fork prep, EIP-8061, EIP-7688.