Implement BAT-006: portfolio-hub ledger integration (REQ-017~019)

- REQ-017: LedgerPort contract (application/ledger_port.py) + portfolio-hub
  adapter + in-memory stub (adapters/ledger/), TREX_PORTFOLIO_HUB_* config
- REQ-018: fill→ledger recording in execution loop; FillStatus carries
  execution_id (deterministic synth) + fee; paper/kis adapters updated
- REQ-019: ledger outbox + retry worker (application/ledger_outbox.py),
  correlation_id idempotency, outcome vocabulary; 002_create_ledger_outbox.sql
- Tests: in-memory/portfolio-hub ledger, execution ledger hook, outbox,
  domain import sweep

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/application/test_ledger_outbox.py

@@ -0,0 +1,65 @@
+"""LedgerOutbox + LedgerWriter direct unit tests (REQ-019)."""
+from __future__ import annotations
+
+from datetime import datetime, timezone
+
+from trex_core.adapters.ledger.in_memory import InMemoryLedger
+from trex_core.application.ledger_outbox import (
+    InMemoryLedgerOutbox,
+    LedgerWriter,
+    OutboxOutcome,
+    WorkItemStatus,
+)
+from trex_core.application.ledger_port import LedgerTrade
+
+
+def _trade(execution_id="paper:PAPER-1:10") -> LedgerTrade:
+    return LedgerTrade(
+        asset_id="PF-1", order_id="PAPER-1", execution_id=execution_id,
+        side="buy", qty=10, price=1000.0,
+        executed_at=datetime(2026, 6, 4, tzinfo=timezone.utc),
+    )
+
+
+def test_enqueue_is_idempotent_on_correlation_id():
+    outbox = InMemoryLedgerOutbox()
+    a = outbox.enqueue(_trade())
+    b = outbox.enqueue(_trade())
+    assert a.correlation_id == b.correlation_id
+    assert len(outbox.all_items()) == 1
+
+
+def test_writer_run_once_drains_pending_and_marks_completed():
+    outbox = InMemoryLedgerOutbox()
+    ledger = InMemoryLedger()
+    writer = LedgerWriter(outbox, ledger)
+    outbox.enqueue(_trade(execution_id="e-1"))
+    outbox.enqueue(_trade(execution_id="e-2"))
+    stats = writer.run_once()
+    assert stats.completed == 2 and ledger.count() == 2
+    assert all(it.status is WorkItemStatus.COMPLETED for it in outbox.all_items())
+    assert all(it.last_outcome is OutboxOutcome.COMPLETED for it in outbox.all_items())
+
+
+def test_writer_marks_conflict_blocked_and_does_not_retry():
+    outbox = InMemoryLedgerOutbox()
+    ledger = InMemoryLedger(conflict_executions={"e-x"})
+    writer = LedgerWriter(outbox, ledger)
+    outbox.enqueue(_trade(execution_id="e-x"))
+    writer.run_once()
+    [item] = outbox.all_items()
+    assert item.status is WorkItemStatus.CONFLICT_BLOCKED
+    assert item.last_outcome is OutboxOutcome.CONFLICT_BLOCKED
+    # No pending items remain, so a subsequent run is a no-op.
+    assert outbox.list_pending() == []
+
+
+def test_writer_retries_until_success():
+    outbox = InMemoryLedgerOutbox()
+    ledger = InMemoryLedger(fail_n_then_succeed=1)
+    writer = LedgerWriter(outbox, ledger)
+    outbox.enqueue(_trade(execution_id="e-r"))
+    s1 = writer.run_once()
+    assert s1.retryable == 1 and ledger.count() == 0
+    s2 = writer.run_once()
+    assert s2.completed == 1 and ledger.count() == 1