class-v3.mjs: a 3-node private network (ports 29600 and up, igneum-devnet-960) on override-60x.json merged with
a CPU genesis difficulty (0x1f010000) and the class switch a few epochs ahead (default 150: inside epoch 2 at
60 DAA per epoch, so the switch rounds up to epoch 3 at DAA 180); one real CPU miner per node; reports blocks on
each side of the boundary, the class and program id of every epoch, rejected blocks (miners and nodes), the
sinks and block counts of every node, and every node's switch line; exit 0 when every check passes.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>