Keryx Node v1.2.3 — Critical consensus fix

MANDATORY UPGRADE

All node operators, pools and miners must upgrade to v1.2.3 as soon as possible.
This release fixes a consensus-level bug that was fragmenting the network.

Why this is mandatory

A flaw in the OPoI fraud-proof slashing path made consensus non-deterministic:
under a burst of AiChallenge transactions, different nodes computed different UTXO
states for the same blocks. The result was mass UTXO commitment is invalid
disqualifications and a chain that fragmented into per-node branches — nodes on
the same version stopped agreeing on the selected chain, and effective network
hashrate dropped.

The same bug also made honest AiResponses slashable, because the verifiable
commitment was no longer carried in the response payload.

What changed

• Disabled the OPoI slashing mechanism. Slashed-escrow enforcement is removed
  (escrows are always spendable) and AiChallenge transactions are no longer
  processed. This makes UTXO computation deterministic again, so upgraded nodes
  re-converge on a single chain.
• Removed the now-dead fraud re-execution path (no more redundant on-chain compute).
• Log/perf cleanups (consensus-neutral).

Important notes

• No hardfork / no activation height. This is a permissive change — just upgrade
  and restart. As nodes adopt v1.2.3, the network heals automatically.
• Slashing is temporarily off. A correct, deterministic slashing mechanism
  (verifiable commitment + first-writer-wins + challenger deposit) will return in a
  future coordinated release (OPoI v2).
• Pre-existing slashed escrows become spendable again by their owners.