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>

.env.example

@@ -1,6 +1,16 @@
 ACCESS_KEY=
 SECRET_KEY=
 
+# Oracle ADB (price_history 저장)
+ORACLE_USER=
+ORACLE_PASSWORD=
+ORACLE_DSN=
+ORACLE_WALLET=
+
+# 추세 판단: N시간 전 대비 +M% 이상이면 상승 중으로 판단
+TREND_HOURS=1
+TREND_MIN_GAIN_PCT=3
+
 # 트레일링 스탑: 최고가 대비 -N% 도달 시 청산
 STOP_LOSS_PCT=5