feat(slot): BAT-028 M2/M3 — universe reconcile + 자산 중심 admission (dcy-020/REQ-058·059)

config 게이트 이중 경로(max_active_slots 설정 시 자산 중심, 미설정 시 legacy pool).
운영 데몬은 cutover(BAT-δ) 전까지 pool 무중단.

- repository: find_slot_by_portfolio·count_active(holding+pending_buy+pending_sell)·
  reconcile_universe(생성 멱등/soft-retire/tombstone, allow_retire 가드) — protocol+in_memory+PG
  (PG: ON CONFLICT (instance_key, portfolio_id) WHERE portfolio_id IS NOT NULL)
- snapshot_scheduler: run_once swap 직후 _reconcile_slots(빈 universe skip, ≥50%↓ retire 보류)
- intents: _admit_buy 모드 분기 + _admit_buy_asset_centric(활성화/already_active/
  capacity_full/unknown_portfolio/over-cap, 인스턴스 lock)
- daemon: instance_key·max_active_slots·reconcile_enabled·trading_date_fn 배선
- 신규 테스트: test_universe_reconcile(6), test_asset_centric_admission(6), PG reconcile(1)

검증: 단위 387 passed / 35 skipped, PG-gated 17 passed, ruff clean. legacy 무파손.
REQ-058/059/060 은 Approved 유지(자산 중심 경로 도입 검증; default 전환·cutover 는 BAT-δ).

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

trex_core/application/intents.py

@@ -85,6 +85,9 @@ class IntentService:
         slot_repo: SlotRepository,
         intent_store: IntentStore,
         resolve_symbol=None,
+        *,
+        instance_key: str = "default",
+        max_active_slots: Optional[int] = None,
     ) -> None:
         self._svc = slot_service
         self._repo = slot_repo
@@ -93,6 +96,11 @@ class IntentService:
         # callable(portfolio_id) -> Optional[str]. When set, admission resolves symbol
         # from the universe and rejects unknown_portfolio if absent.
         self._resolve_symbol = resolve_symbol
+        # dcy-020 / REQ-059 (BAT-028): asset-centric mode gate. When max_active_slots
+        # is set, buy admission activates the asset's permanent slot under an M cap
+        # (FCFS, no eviction); otherwise the legacy pool path runs (unchanged).
+        self._instance_key = instance_key
+        self._max_active_slots = max_active_slots
 
     # ------------------------------------------------------------
     def lookup(self, intent_id: str) -> Optional[IntentDecision]:
@@ -163,6 +171,9 @@ class IntentService:
         elif not symbol:
             # No resolver wired and no symbol carried — cannot determine the order target.
             return IntentDecision(intent.intent_id, "rejected", None, "unknown_portfolio")
+        # dcy-020 / REQ-059 (BAT-028): asset-centric admission when M is configured.
+        if self._max_active_slots is not None:
+            return self._admit_buy_asset_centric(intent, symbol)
         # Retry on the last-candidate race: another intent may claim the slot
         # between our find and transit (SlotStateMismatchError).
         # dcy-019 / REQ-007: admission candidate is idle ∪ closed (closed-slot
@@ -199,6 +210,48 @@ class IntentService:
             return IntentDecision(intent.intent_id, "admitted", updated.slot_id, None)
         return IntentDecision(intent.intent_id, "rejected", None, "idle_slot_contended")
 
+    # ------------------------------------------------------------
+    def _admit_buy_asset_centric(self, intent: BuyIntent, symbol: str) -> IntentDecision:
+        """dcy-020 / REQ-059: activate the asset's permanent slot under the M cap.
+
+        FCFS + no eviction: if the asset is already active -> already_active; if the
+        instance is at M active slots -> capacity_full (existing holdings untouched,
+        incl. over-cap when M is lowered). Single intent thread + instance-scoped
+        advisory lock serialize admissions (REQ-002 NFR-1 / dcy-020 OQ-1)."""
+        _ACTIVE = (SlotState.PENDING_BUY, SlotState.HOLDING, SlotState.PENDING_SELL)
+        for _ in range(_MAX_IDLE_RETRY):
+            slot = self._repo.find_slot_by_portfolio(self._instance_key, intent.portfolio_id)
+            if slot is None:
+                # no asset slot for this instance (not in reconciled universe)
+                return IntentDecision(intent.intent_id, "rejected", None, "unknown_portfolio")
+            if slot.status in _ACTIVE:
+                return IntentDecision(intent.intent_id, "rejected", None, "already_active")
+            if self._repo.count_active(self._instance_key) >= self._max_active_slots:
+                return IntentDecision(intent.intent_id, "rejected", None, "capacity_full")
+            try:
+                updated = self._svc.transit_slot(
+                    slot.slot_id,
+                    slot.status,
+                    SlotState.PENDING_BUY,
+                    reason="buy_intent",
+                    actor="intent_api",
+                    symbol=symbol,
+                    qty=intent.qty,
+                    allocated_capital=intent.allocated_capital,
+                    limit_price=intent.entry_price,
+                    strategy_id=intent.strategy_id,
+                    sell_strategy_id=intent.sell_strategy_id,
+                    portfolio_id=intent.portfolio_id,
+                    forced_close_at=intent.forced_close_at,
+                    stop_loss_price=intent.stop_loss_price,
+                    take_profit_price=intent.take_profit_price,
+                    extra={"intent_id": intent.intent_id, "symbol": symbol},
+                )
+            except SlotStateMismatchError:
+                continue  # slot changed under us; re-fetch and re-evaluate
+            return IntentDecision(intent.intent_id, "admitted", updated.slot_id, None)
+        return IntentDecision(intent.intent_id, "rejected", None, "already_active")
+
     def _admit_sell(self, intent: SellIntent) -> IntentDecision:
         slot = self._repo.fetch_slot(intent.slot_id)
         if slot is None: