feat: add portfolio snapshot read layer

.env.example

@@ -37,6 +37,14 @@ TREX_PORTFOLIO_HUB_TIMEOUT=5
 # Ledger outbox writer tick interval (seconds).
 TREX_LEDGER_INTERVAL_SEC=1.0
 
+# --- Snapshot scheduler (REQ-030, BAT-008) ---
+# Daily snapshot refresh time (KST, 24h HH:MM). The scheduler also runs once on
+# daemon boot regardless of this time.
+TREX_SNAPSHOT_SCHEDULE_KST=07:30
+# Scheduler tick interval (seconds) — how often it checks whether the schedule
+# time has passed. 60s is plenty for a once-a-day refresh.
+TREX_SNAPSHOT_TICK_SEC=60
+
 # --- RabbitMQ transport (REQ-022, BAT-007) ---
 # trex-core ↔ 전략 모듈 통신은 RabbitMQ(AMQP) 메시지 기반 (HTTP /v1 API 는 제거됨).
 # 미설정이면 데몬은 InMemoryTransport stub 으로 기동(개발/CI 용; 전략과 통신 불가).