feat: replace volatility breakout with DB-backed real-time trend check

- price_history table on Oracle ADB stores prices every 10 minutes
- check_trend(): current price vs N hours ago (default 1h, +3% threshold)
- check_momentum(): unchanged (MA20 + 2x volume still applies)
- Ticker list cached 5 minutes to avoid 429 rate limits
- Collector starts 30s after boot to avoid simultaneous API calls
- Configurable: TREND_HOURS, TREND_MIN_GAIN_PCT in .env

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

core/price_db.py

@@ -0,0 +1,91 @@
+"""Oracle ADB price_history CRUD."""
+
+from __future__ import annotations
+
+import os
+from contextlib import contextmanager
+from typing import Generator, Optional
+
+import oracledb
+
+_pool: Optional[oracledb.ConnectionPool] = None
+
+
+def _get_pool() -> oracledb.ConnectionPool:
+    global _pool
+    if _pool is None:
+        kwargs: dict = dict(
+            user=os.environ["ORACLE_USER"],
+            password=os.environ["ORACLE_PASSWORD"],
+            dsn=os.environ["ORACLE_DSN"],
+            min=1,
+            max=3,
+            increment=1,
+        )
+        wallet = os.environ.get("ORACLE_WALLET")
+        if wallet:
+            kwargs["config_dir"] = wallet
+        _pool = oracledb.create_pool(**kwargs)
+    return _pool
+
+
+@contextmanager
+def _conn() -> Generator[oracledb.Connection, None, None]:
+    pool = _get_pool()
+    conn = pool.acquire()
+    try:
+        yield conn
+        conn.commit()
+    except Exception:
+        conn.rollback()
+        raise
+    finally:
+        pool.release(conn)
+
+
+def insert_prices(ticker_prices: dict[str, float]) -> None:
+    """여러 종목의 현재가를 한 번에 저장."""
+    if not ticker_prices:
+        return
+    rows = [(ticker, price) for ticker, price in ticker_prices.items()]
+    sql = "INSERT INTO price_history (ticker, price) VALUES (:1, :2)"
+    with _conn() as conn:
+        conn.cursor().executemany(sql, rows)
+
+
+def get_price_n_hours_ago(ticker: str, hours: float) -> Optional[float]:
+    """N시간 전 가장 가까운 가격 반환. 데이터 없으면 None."""
+    sql = """
+        SELECT price FROM price_history
+         WHERE ticker = :ticker
+           AND recorded_at BETWEEN
+               SYSTIMESTAMP - INTERVAL ':h' HOUR - INTERVAL '10' MINUTE
+               AND SYSTIMESTAMP - INTERVAL ':h' HOUR + INTERVAL '10' MINUTE
+         ORDER BY ABS(CAST(recorded_at AS DATE) -
+                      CAST(SYSTIMESTAMP - INTERVAL ':h' HOUR AS DATE))
+         FETCH FIRST 1 ROWS ONLY
+    """
+    # Oracle INTERVAL bind param 미지원으로 직접 포맷
+    h = int(hours)
+    sql = f"""
+        SELECT price FROM price_history
+         WHERE ticker = :ticker
+           AND recorded_at BETWEEN
+               SYSTIMESTAMP - ({h}/24) - (10/1440)
+               AND SYSTIMESTAMP - ({h}/24) + (10/1440)
+         ORDER BY ABS(CAST(recorded_at AS DATE) -
+                      CAST(SYSTIMESTAMP - ({h}/24) AS DATE))
+         FETCH FIRST 1 ROWS ONLY
+    """
+    with _conn() as conn:
+        cursor = conn.cursor()
+        cursor.execute(sql, {"ticker": ticker})
+        row = cursor.fetchone()
+    return float(row[0]) if row else None
+
+
+def cleanup_old_prices(keep_hours: int = 48) -> None:
+    """N시간 이상 오래된 데이터 삭제 (DB 용량 관리)."""
+    sql = f"DELETE FROM price_history WHERE recorded_at < SYSTIMESTAMP - ({keep_hours}/24)"
+    with _conn() as conn:
+        conn.cursor().execute(sql)