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/runtime/config.py

@@ -0,0 +1,27 @@
+"""Daemon configuration resolution (REQ-005)."""
+from __future__ import annotations
+
+import os
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class DaemonConfig:
+    dsn: str
+    total_slots: int
+    host: str
+    port: int
+
+    @staticmethod
+    def from_env() -> "DaemonConfig":
+        dsn = os.environ.get("TREX_POSTGRESQL_DSN")
+        if not dsn:
+            raise RuntimeError(
+                "TREX_POSTGRESQL_DSN is required to start the slot-core daemon."
+            )
+        return DaemonConfig(
+            dsn=dsn,
+            total_slots=int(os.environ.get("TREX_TOTAL_SLOTS", "10")),
+            host=os.environ.get("TREX_API_HOST", "127.0.0.1"),
+            port=int(os.environ.get("TREX_API_PORT", "8080")),
+        )