fix(reconcile): symbol을 슬롯 생성 시 함께 저장 + NULL 슬롯 backfill

reconcile_universe 시그니처를 set[str] → dict[str, str] (portfolio_id→symbol)로 변경.
기존 symbol=NULL 슬롯은 다음 reconcile 실행 시 자동 backfill.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tests/adapters/persistence/test_postgresql_repository.py

@@ -29,22 +29,22 @@ def test_universe_reconcile_pg(pg_clean):
     # partial-index upsert + find_slot_by_portfolio/count_active.
     repo = PostgreSQLSlotRepository(pg_clean)
     inst = "inst-pg"
-    r1 = repo.reconcile_universe(inst, {"pf-a", "pf-b"})
+    r1 = repo.reconcile_universe(inst, {"pf-a": "SYM", "pf-b": "SYM"})
     assert r1["created"] == 2
-    r2 = repo.reconcile_universe(inst, {"pf-a", "pf-b"})  # idempotent (ON CONFLICT)
+    r2 = repo.reconcile_universe(inst, {"pf-a": "SYM", "pf-b": "SYM"})  # idempotent (ON CONFLICT)
     assert r2["created"] == 0
     slot_a = repo.find_slot_by_portfolio(inst, "pf-a")
     assert slot_a is not None and slot_a.status is SlotState.INACTIVE
     assert repo.count_active(inst) == 0
     # pf-b leaves universe while inactive -> soft-retire
-    r3 = repo.reconcile_universe(inst, {"pf-a"})
+    r3 = repo.reconcile_universe(inst, {"pf-a": "SYM"})
     assert r3["retired"] == 1
     assert repo.find_slot_by_portfolio(inst, "pf-b").retired_at is not None
 
 
 def test_capacity_instance_scoped(pg_clean):
     repo, svc, _ = _wire(pg_clean)
-    repo.reconcile_universe(INST, set(_SYMS))
+    repo.reconcile_universe(INST, _SYMS)
     cap = svc.compute_slot_capacity()
     assert cap.inactive_count == 3 and cap.available_count == 3
     cap_m = svc.compute_slot_capacity(max_active_slots=2)
@@ -54,7 +54,7 @@ def test_capacity_instance_scoped(pg_clean):
 
 def test_buy_intent_persists_transition(pg_clean):
     repo, svc, intents = _wire(pg_clean)
-    repo.reconcile_universe(INST, set(_SYMS))
+    repo.reconcile_universe(INST, _SYMS)
     d = intents.submit_buy(BuyIntent(intent_id="pg-buy-1", qty=10, portfolio_id="PF-1"))
     assert d.admitted
     slot = repo.fetch_slot(d.slot_id)
@@ -63,7 +63,7 @@ def test_buy_intent_persists_transition(pg_clean):
 
 def test_buy_intent_idempotent_on_pg(pg_clean):
     repo, svc, intents = _wire(pg_clean)
-    repo.reconcile_universe(INST, set(_SYMS))
+    repo.reconcile_universe(INST, _SYMS)
     d1 = intents.submit_buy(BuyIntent(intent_id="pg-dup", portfolio_id="PF-1"))
     d2 = intents.submit_buy(BuyIntent(intent_id="pg-dup", portfolio_id="PF-1"))
     assert d1.slot_id == d2.slot_id and d2.status == "admitted"
@@ -74,7 +74,7 @@ def test_buy_intent_idempotent_on_pg(pg_clean):
 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)
-    repo.reconcile_universe(INST, set(_SYMS))
+    repo.reconcile_universe(INST, _SYMS)
     slot = repo.find_slot_by_portfolio(INST, "PF-2")
     d = intents.submit_buy(BuyIntent(intent_id="pg-sid", slot_id=slot.slot_id))
     assert d.admitted and d.slot_id == slot.slot_id
@@ -85,7 +85,7 @@ def test_full_lifecycle_returns_to_inactive_and_reuses(pg_clean):
     # dcy-020 (BAT-030): sell fill -> inactive (occupancy cleared, asset
     # binding kept); the same permanent slot activates again.
     repo, svc, intents = _wire(pg_clean)
-    repo.reconcile_universe(INST, set(_SYMS))
+    repo.reconcile_universe(INST, _SYMS)
     d = intents.submit_buy(BuyIntent(intent_id="pg-life", portfolio_id="PF-1"))
     sid = d.slot_id
     svc.transit_slot(sid, SlotState.PENDING_BUY, SlotState.HOLDING,
@@ -106,8 +106,8 @@ def test_dispatch_queue_instance_scoped(pg_clean):
     # dcy-020/REQ-056 (BAT-030): list_undispatched_pending / list_dispatched_pending
     # never cross instance boundaries in a shared DB.
     repo_a = PostgreSQLSlotRepository(pg_clean)
-    repo_a.reconcile_universe("inst-a", {"pf-x"})
-    repo_a.reconcile_universe("inst-b", {"pf-x"})
+    repo_a.reconcile_universe("inst-a", {"pf-x": "SYM"})
+    repo_a.reconcile_universe("inst-b", {"pf-x": "SYM"})
     svc_a = SlotService(repo_a, instance_key="inst-a")
     slot_a = repo_a.find_slot_by_portfolio("inst-a", "pf-x")
     svc_a.transit_slot(slot_a.slot_id, SlotState.INACTIVE, SlotState.PENDING_BUY,