dash(replay-fold): mirror GetBlockTxOuts operator-reward split in the payee cross-check (h=1439234 sub-class)

[frstrtr]

What

Port dashd's operator-reward split into the DML replay fold's pass-6 payee
cross-check so the projected payee matches dashd at h=1439234 and for the
whole event sub-class.

Why (live poison)

The daemonless self-derive hard-stopped:

[REPLAY-PAYEE] G1 fold POISONED: DML FOLD PAYEE MISMATCH at h=1439234 --
this block's coinbase does not pay the projected masternode
71ed3bf5...ceb2d006 -- the merkleRootMNList self-check PASSED at this height

The projection was correct — dashd paid the very MN c2pool projected. The
check was blind to the DIP3 operator-reward split:

• proTxHash 71ed3bf5...ceb2d006, registered h=1434598, nOperatorReward=0x2710 = 10000 bps = 100.00%, owner==operator self-host.
• dashd masternode/payments.cpp GetBlockTxOuts:64-77: at bps=10000 the
  operator reward eats the whole MN share, masternodeReward folds to exactly
  0, so the ONLY MN output emitted (and required by IsTransactionValid:109-139)
  is scriptOperatorPayout. scriptPayout is legitimately absent.
• Block 1439234 paid the operator script for the full 1.51818084 with no owner
  remainder; roots matched 411073/411073. The fold demanded scriptPayout and
  false-poisoned a byte-correct fold.

This recurs for every 100%-operator-reward payment (~one queue length apart
while registered), so a point patch would re-wedge — the general dashd-faithful
branch is required.

The fix (replay_fold_engine.hpp)

• Pass 0b now captures the payee's full pre-block tuple
  (scriptPayout, scriptOperatorPayout, nOperatorReward) — state already held by
  fold_proreg/fold_proupserv.
• Pass 6 mirrors GetBlockTxOuts without needing amounts:
  • bps==10000 && operator-script set → require scriptOperatorPayout, not
    scriptPayout (dashd emits none);
  • 0<bps<10000 → masternodeReward = mnShare - floor(mnShare*bps/10000) is
    provably >0, so require scriptPayout (unchanged); the operator output's
    exact amount needs the fee reward the fold cannot price (W5 gap), so never
    poison on the operator axis for a partial split;
  • otherwise → require scriptPayout (unchanged).
• The poison message now dumps {scriptPayout, scriptOperatorPayout, bps} so any
  future instance self-classifies.

Passes 0/5 (projection + nLastPaidHeight bookkeeping) are untouched — they were
correct; the projected proTxHash equals the paid MN here.

Reward-safe by construction

Check-only change on the verification axis. The requirement becomes exactly
dashd's required-output set, never weaker: at bps=10000 a coinbase paying
scriptPayout instead of the operator output still hard-stops (dashd would
reject it too). The merkleRootMNList SET self-check stays unconditional; the
payee projection + nLastPaidHeight bookkeeping stay derived. No live-mint
behaviour changes.

Tests (DashReplayFoldOperatorSplit, red→green proven)

• FullOperatorRewardPaysOperatorScriptFoldsThrough — the h=1439234 shape; RED
  on the old selection (poisons a byte-correct fold), GREEN with the faithful
  branch.
• FullOperatorRewardPayingOwnerScriptStillPoisons — strictness: a bps=10000
  coinbase paying the owner script is invalid and still poisons.
• PartialOperatorRewardRequiresOwnerScript / ...MissingOwnerScriptPoisons —
  partial splits keep requiring scriptPayout, unchanged.

Build / verification

• -DC2POOL_DASH_BLS=ON (real dashbls, relic-backed) — c2pool-dash self-reports
  at init: DASH BLS backend: REAL (dashbls linked; quorum-commitment verify armed).
• test_dash_mn_state: 130 passed, 1 skipped (data-driven), 0 failed.

Stacked on integrator/dashd-cut-early-quorum-memberset (#1277 branch). DRAFT
— do not merge.

[frstrtr]

Superseded by #1293 (combined fetch+fold onion). This branch's head commit is present in #1293 by exact SHA (verified via triage). Closing to reconcile the draft backlog; the branch is preserved (not deleted) — reopen if #1293 changes course.