Bitcoin Core Merges Production AssumeUTXO Support

Bitcoin Core merged production support for loading an assumed UTXO set while continuing full historical validation in the background. The design can shorten the time before a new node becomes usable without changing consensus rules or eliminating eventual verification of the chain history.

The implementation affected direct Bitcoin Core architecture. It changed software or infrastructure behavior without implying a new Bitcoin consensus rule unless the underlying sources explicitly established one.

The Bitcoin connection ran through bitcoin Core architecture. Production-stage milestone improving node bootstrapping while retaining full validation.