Deliver BAT-002: slot-core daemon + HTTP intent API + PostgreSQL

Implement REQ-005~009 (dcy-002 slice 1) as an onion stack on top of the
BAT-001 pure domain:
- application: IntentService (admission + single-writer transition +
  intent_id idempotency via durable intent_log)
- adapters/persistence: PostgreSQLSlotRepository + PostgreSQLIntentStore +
  trex-core-owned migrations (daily_slot per Appendix A, daily_symbol_entries,
  slot_transition_log, intent_log) + in-memory intent store
- adapters/api: FastAPI /v1 (healthz, intents/buy|sell|{id}, slots, capacity)
- runtime: trex-core-daemon entrypoint with lifespan migrate+preallocate

Verification (against local PostgreSQL 18): 74 passed, ruff clean, domain
import sweep shows zero web/db deps (NFR-1), 20-thread concurrency admits
exactly the idle count (NFR-2), idempotent resubmit causes no double
transition (NFR-3), EXPECTED_SLOT_FIELDS<->information_schema drift test
(realizes dcy-001 OQ-2's deferred DB-side check), and a daemon E2E smoke.

Align all four baseline docs to the new daemon/API/persistence layers.
BAT-002 -> release-candidate; REQ-005~009 -> Implemented. Full async outbox,
broker execution, safety floor, and strategy daemons remain deferred to a
follow-up Discovery.

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

trex_core/adapters/api/schemas.py

@@ -0,0 +1,61 @@
+"""Pydantic request/response schemas for the /v1 HTTP API (REQ-007/008)."""
+from __future__ import annotations
+
+from datetime import date, datetime
+from typing import Optional
+from uuid import UUID
+
+from pydantic import BaseModel
+
+
+class BuyIntentRequest(BaseModel):
+    intent_id: str
+    trading_date: date
+    symbol: str
+    qty: Optional[float] = None
+    allocated_capital: Optional[float] = None
+    entry_price: Optional[float] = None
+    strategy_id: Optional[str] = None
+    sell_strategy_id: Optional[str] = None
+    portfolio_id: Optional[str] = None
+    forced_close_at: Optional[datetime] = None
+
+
+class SellIntentRequest(BaseModel):
+    intent_id: str
+    slot_id: UUID
+    reason: str = "discretionary_sell"
+    sell_strategy_id: Optional[str] = None
+
+
+class IntentResponse(BaseModel):
+    intent_id: str
+    status: str
+    slot_id: Optional[UUID] = None
+    reason: Optional[str] = None
+
+
+class SlotSnapshot(BaseModel):
+    slot_id: UUID
+    trading_date: date
+    status: str
+    symbol: Optional[str] = None
+    qty: Optional[float] = None
+    avg_price: Optional[float] = None
+    entry_price: Optional[float] = None
+    allocated_capital: Optional[float] = None
+    strategy_id: Optional[str] = None
+    sell_strategy_id: Optional[str] = None
+    forced_close_at: Optional[datetime] = None
+
+
+class CapacityResponse(BaseModel):
+    idle_count: int
+    holding_count: int
+    pending_count: int
+    total_slots: int
+    scarcity_ratio: float
+
+
+class HealthResponse(BaseModel):
+    status: str = "ok"