Abandon a transaction only on proof, and keep watching failed rows (B-78, TX-15, TX-17, TX-23, TX-26, ELC-28, DAT-33, DAT-36, DAT-69, DAT-72, AUD-11, AUD-12, AUD-31, AUD-39, API-32)

reconcile_once abandoned a row when the *active* server's history lacked its txid:
after 120s for `building` (which a restart onto a different server makes likely),
after 6h for `pending`, and all at once after a forward clock jump. It re-checked the
status but not the txid, so it raced the bumper, and a `failed` row was never looked at
again.

- The reconciler asks every server (ElectrumListener.get_histories, active + others) for
  the history of the row's address and looks for every txid of the row. Present on any
  server -> promoted (adopting the version found). Absent is only "no server of the
  quorum knows it" and needs the active server plus the quorum minimum of the others to
  have answered; even then nothing is released without proof:
  (a) an input spent in a block by a transaction that is none of the row's versions,
      agreed by a strict majority of a quorum of the other servers (confirmed_spender), or
  (b) a rebroadcast of the latest raw tx to every server (rebroadcast_everywhere)
      refused by all of them, explicitly, for missing/spent inputs.
  Accepted or "already known" by any server means alive; a fee refusal is not proof
  (`building` -> `pending` for the bumper, `pending` untouched); too few answers or
  anything else leaves the row alone. failure_reason names the proof.
- The write re-reads status *and* current_txid under begin_immediate (TX-26).
- pending_transactions.failed_at (set by _abandon and _release_failed_withdrawal) starts
  a 14-day watch: a failed row that a majority of the other servers (at least the quorum
  minimum) list in a block becomes `confirmed`, writes pending_tx_resurrected once and
  pauses the lottery with paused_reason `resurrected_tx`; linked rows are not corrected.
  The confirmation is by quorum of histories for now; merkle proofs come with B-83.
- round_config.paused_reason (migration b7d2e41c9a05, with the failed_at one): `operator`
  from POST /admin/pause (which accepts an optional `note` and never overwrites an
  automatic reason), cleared by resume, which logs the reason it lifted; exposed on
  /admin/config and GET /rounds/current. rounds/pause.py:pause_automatically is the
  system's way in.
- PendingTransactionReconciler takes the listener as `network`; with none it can promote
  but never abandon.

Tests changed because the spec changed: the three reconciler tests that expect an
abandonment (and the one in test_tx_versions) now supply a network that proves the
transaction is gone.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

app/rounds/pause.py

@@ -0,0 +1,30 @@
+"""Pausing the lottery from code (B-78, DAT-69, AUD-11).
+
+A pause only stops the *next* round from opening (rounds/service.py:rounds_can_open); a
+round in progress still closes, draws and pays. Besides the operator's own switch there
+are pauses the system raises itself when something needs a human look — a transaction
+given up for dead that confirmed after all (`resurrected_tx`, B-78) and, in later
+findings, a deep reorg (`reorg`, B-85) and a payout whose winning bet left the chain
+(`payout_blocked`, B-82).
+"""
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.audit.log import write_audit_log
+from app.rounds.config import get_round_config
+
+OPERATOR_REASON = "operator"
+AUTOMATIC_REASONS = ("reorg", "payout_blocked", "resurrected_tx")
+
+
+async def pause_automatically(session: AsyncSession, reason: str) -> None:
+    """Pause the lottery for an automatic `reason` in the caller's transaction and write
+    the `lottery_paused` row. An automatic reason is written even over a pause that is
+    already active (DAT-69): the cause that needs checking must not be hidden behind an
+    earlier one, and an operator pause is never what overrides it."""
+    if reason not in AUTOMATIC_REASONS:
+        raise ValueError(f"not an automatic pause reason: {reason!r}")
+    config = await get_round_config(session)
+    config.paused = True
+    config.paused_reason = reason
+    await write_audit_log(session, "lottery_paused", {"reason": reason})