perf(slots): BAT-040 — slots RPC DB-level status 필터 (REQ-002/006/073, issue #25)

REQ-002/006 change-req(CHG-20260612-01)→구현→confirm-req-implemented,
REQ-073 change-req(CHG-20260612-02, 관찰 계약 불변 Implemented 유지) 전체 delivery.

- repository.py/in_memory_repository.py: SlotRepository.list_slots(instance_key,
  status_filter=None) — status 값 집합 필터, None=전체(기존 호출자 불변).
- postgresql.py: list_slots DB-level WHERE status = ANY(%s) (full scan + Python
  필터 제거). 스키마/마이그레이션 변경 없음.
- messaging_handlers.py: _FILTER_STATUS 매핑으로 filter→status 집합 위임,
  watchdog 갱신용 holding 조회를 all/holding fetch 결과에서 재사용(2nd 커넥션 생략).
- 관찰 가능한 RPC 계약(REQ-073 AC-1~6) 불변 — 동작 보존 최적화.
- tests: in-memory status_filter 5종 + PG 게이트 1종. 439 passed (+5), ruff clean.

REQ-002·006 Approved→Implemented, REQ-073 Implemented 유지, BAT-040 release-candidate.
issue #25 close.

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

tests/adapters/persistence/test_postgresql_repository.py

@@ -71,6 +71,19 @@ def test_buy_intent_idempotent_on_pg(pg_clean):
     assert len(pending) == 1  # no double transition
 
 
+def test_list_slots_status_filter_pg(pg_clean):
+    # REQ-006 CHG-20260612-01 (issue #25): DB-level status filter (status = ANY).
+    repo, svc, intents = _wire(pg_clean)
+    repo.reconcile_universe(INST, _SYMS)  # 3 inactive
+    intents.submit_buy(BuyIntent(intent_id="pg-f1", qty=10, portfolio_id="PF-1"))  # PF-1 -> pending_buy
+
+    assert len(repo.list_slots(INST)) == 3                                  # None -> all
+    assert len(repo.list_slots(INST, status_filter={"inactive"})) == 2
+    pending = repo.list_slots(INST, status_filter={"pending_buy", "pending_sell"})
+    assert len(pending) == 1 and pending[0].status is SlotState.PENDING_BUY
+    assert repo.list_slots(INST, status_filter={"error"}) == []
+
+
 def test_buy_by_slot_id_contract_pg(pg_clean):
     # dcy-020/REQ-061: slot_id is the canonical buy key against real PG.
     repo, svc, intents = _wire(pg_clean)