Elektron Net v4.0.2

Release v4.0.2 - MuHash UTXO Attestation Mainnet Activation

Mandatory update before block height 137000.

Starting at block height 137000, the network switches to a more
efficient UTXO attestation method (incremental MuHash accumulator
instead of a full rescan at every checkpoint). Nodes running older
software will validate the attestation incorrectly from that height
onward and fall off the main network.

If you update before reaching that height, you won't notice the
switch at all. If you miss it: your node automatically detects that
its own chain has fallen behind and resyncs itself via a checkpoint
snapshot once the current software is running — nothing is lost,
just unnecessary downtime.

Details:
- Changelog: https://github.com/kutlusoy/elektron-net/blob/main/doc-elektron/CHANGELOG-muhash-attestation.md
- Technical diff reference: https://github.com/kutlusoy/elektron-net/blob/main/doc-elektron/BITCOIN_CORE_DIFF.md