feat(slot,intent): slot strategy-state 저장소 (dcy-028) + sell retryable 플래그 (issue #27)

BAT-042 (dcy-028 / issue #26 C-1/C-2/C-2b/C-3, REQ-079~082 + REQ-073/074 CHG):
- slot_strategy_state 별도 테이블 + StrategyStateStore(in-memory+PG) + occupancy_seq·version CAS + opaque UTF-8 data + 2단 size cap (REQ-079)
- trex.slots.strategy_state.set write RPC — reject reason 집합, 멱등 (REQ-080)
- Slot.occupancy_seq 필드 + inactive→pending_buy bump + →INACTIVE close 삭제 훅 → 점유 전환 ABA 구조적 차단 (REQ-081)
- slots.req 응답 행에 strategy_state 맵(batched 조립)·occupancy_seq additive (REQ-073 AC-7/REQ-074 AC-6)
- 마이그레이션 014(occupancy_seq)/015(slot_strategy_state), baseline 문서 정합 (REQ-082)

BAT-043 (issue #27 / REQ-007 CHG):
- rejected SellIntent 응답에 additive retryable: bool (core 소유 reason→retryable 매핑, 미인식 기본 true, bad_request* false) — 손절매 재시도 안전 경로 decoupling

검증: 487 passed, 47 skipped (신규 41: store CAS 6+ABA, occupancy bump/close 4경로, set RPC 9, slots read 5, retryable 8, PG 게이트), ruff clean.
REQ-079·080·081·082·073·074·007 → Implemented. issue #27 close. PG 경로 실 DB 검증은 release 위임.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/adapters/persistence/test_postgresql_repository.py

@@ -130,3 +130,47 @@ def test_dispatch_queue_instance_scoped(pg_clean):
     repo_a.mark_dispatched(slot_a.slot_id, "ord-1")
     assert [s.slot_id for s in repo_a.list_dispatched_pending("inst-a")] == [slot_a.slot_id]
     assert repo_a.list_dispatched_pending("inst-b") == []
+
+
+# dcy-028 / REQ-079·081 (BAT-042): strategy-state store + occupancy_seq column
+def test_strategy_state_store_pg(pg_clean):
+    from trex_core.adapters.persistence.postgresql import PgStrategyStateStore
+    from trex_core.application import strategy_state as ss
+
+    repo = PostgreSQLSlotRepository(pg_clean)
+    store = PgStrategyStateStore(pg_clean)
+    svc = SlotService(repo, instance_key=INST, strategy_state_store=store)
+    repo.reconcile_universe(INST, {"pf-a": "005930"})
+    slot = repo.find_slot_by_portfolio(INST, "pf-a")
+    svc.transit_slot(slot.slot_id, SlotState.INACTIVE, SlotState.PENDING_BUY,
+                     reason="buy", actor="t")
+    svc.transit_slot(slot.slot_id, SlotState.PENDING_BUY, SlotState.HOLDING,
+                     reason="filled", actor="t", qty=10, avg_price=100)
+    # occupancy_seq persisted
+    held = repo.fetch_slot(slot.slot_id)
+    assert held.occupancy_seq == 1
+
+    # first-create
+    r1 = store.set(slot.slot_id, "tsl_v1", expected_version=0,
+                   expected_occupancy_seq=1, data="peak", current_occupancy_seq=1,
+                   slot_active=True)
+    assert r1.ok and r1.version == 1
+    # version conflict
+    r2 = store.set(slot.slot_id, "tsl_v1", expected_version=0,
+                   expected_occupancy_seq=1, data="stale", current_occupancy_seq=1,
+                   slot_active=True)
+    assert not r2.ok and r2.reason == ss.REASON_VERSION_CONFLICT
+    # batched read
+    got = store.get_for_slots([slot.slot_id], {slot.slot_id: 1})
+    assert got[slot.slot_id]["tsl_v1"].data == "peak"
+
+    # close deletes state (C-3)
+    svc.transit_slot(slot.slot_id, SlotState.HOLDING, SlotState.PENDING_SELL,
+                     reason="sell", actor="t")
+    svc.transit_slot(slot.slot_id, SlotState.PENDING_SELL, SlotState.INACTIVE,
+                     reason="sold", actor="t")
+    assert store.get_for_slots([slot.slot_id], {slot.slot_id: 1}) == {}
+    # reuse bumps occupancy_seq
+    reused = svc.transit_slot(slot.slot_id, SlotState.INACTIVE, SlotState.PENDING_BUY,
+                              reason="buy", actor="t")
+    assert reused.occupancy_seq == 2