feat(cassettes): consume the machine's operation acknowledgements

The machine echoes the operation ids it has applied in its state
document, and this records them. That echo is the only acknowledgement
this transport can carry: an addressable event gives its publisher no
failure signal at all, since the relay returns OK for an event it then
discards. Without it the dashboard could only ever show an operation as
sent, never as delivered.

Deliberately not gated on whether the state event advanced the counts.
The machine echoes its applied ids on every publish, heartbeats included,
so an event carrying nothing new about the counts can still be the first
one to tell us an operation landed.

The consumer goes in before the producer on purpose. The machine does not
send applied_ops yet, and every new field on the state payload defaults to
a value meaning "this machine does not report that yet" rather than to
one that would be wrong — an absent list reads as nothing acknowledged,
which is exactly right for a machine that has applied nothing.

Also picks up seq and counts_uncertain_since, which the machine already
publishes and this side was dropping on the floor.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tests/test_cassette_ops.py

@@ -15,7 +15,7 @@ from datetime import datetime, timezone
 import pytest
 from pydantic import ValidationError
 
-from .. import cassette_transport
+from .. import cassette_transport, tasks
 from ..crud import _should_ack_op
 from ..models import (
     CASSETTE_OP_TYPES,
@@ -23,6 +23,7 @@ from ..models import (
     CreateCassetteOpData,
     Machine,
     PublishCassetteOpsPayload,
+    PublishCassettesPayload,
 )
 
 AT = datetime.fromtimestamp(1790106060, timezone.utc)
@@ -257,3 +258,62 @@ class TestPublishOpsToAtm:
         m = machine().copy(update={"machine_npub": npub})
         await cassette_transport.publish_ops_to_atm(m, [], "op1")
         assert captured["d_tag"] == f"bitspire-cassettes:{ATM_HEX}"
+
+
+# =============================================================================
+# _record_op_acknowledgements — the only ack this transport can carry
+# =============================================================================
+
+
+def state_payload(**kw) -> PublishCassettesPayload:
+    base = {"positions": {"1": {"denomination": 50, "count": 24}}}
+    return PublishCassettesPayload(**{**base, **kw})
+
+
+class TestRecordOpAcknowledgements:
+    @pytest.mark.asyncio
+    async def test_marks_the_reported_ids(self):
+        calls = []
+
+        async def mark(machine_id, op_ids):
+            calls.append((machine_id, op_ids))
+            return len(op_ids)
+
+        await tasks._record_op_acknowledgements(
+            "m1", state_payload(applied_ops=["a", "b"]), mark
+        )
+        assert calls == [("m1", ["a", "b"])]
+
+    @pytest.mark.asyncio
+    async def test_does_nothing_when_the_machine_reports_none(self):
+        """An older machine sends no applied_ops at all, and a new one with
+        nothing applied sends an empty list. Neither should write."""
+        calls = []
+
+        async def mark(machine_id, op_ids):
+            calls.append((machine_id, op_ids))
+            return 0
+
+        await tasks._record_op_acknowledgements("m1", state_payload(), mark)
+        await tasks._record_op_acknowledgements(
+            "m1", state_payload(applied_ops=[]), mark
+        )
+        assert calls == []
+
+    @pytest.mark.asyncio
+    async def test_acks_even_when_the_counts_were_not_newer(self):
+        """The machine echoes its applied ids on every publish, including
+        heartbeats that carry nothing new about the counts. One of those can
+        still be the first event to tell us an operation landed, so the ack
+        must not depend on the state having advanced."""
+        seen = []
+
+        async def mark(machine_id, op_ids):
+            seen.extend(op_ids)
+            return len(op_ids)
+
+        # Same positions as already on file — a pure heartbeat.
+        await tasks._record_op_acknowledgements(
+            "m1", state_payload(applied_ops=["late-ack"]), mark
+        )
+        assert seen == ["late-ack"]