feat: add Telegram notifications and configurable stop loss

- notify.py: buy/sell/error alerts via upbit_trading_jm_bot
- STOP_LOSS_PCT: trailing stop configurable via .env (default -5%)
- notify_buy/notify_sell called on every trade execution

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

core/trader.py

@@ -11,6 +11,7 @@ from typing import Optional
 
 import pyupbit
 from dotenv import load_dotenv
+from .notify import notify_buy, notify_sell, notify_error
 
 load_dotenv()
 
@@ -80,9 +81,11 @@ def buy(ticker: str) -> bool:
                 f"[매수] {ticker} @ {current:,.0f}원 | "
                 f"수량={amount} | 투자금={order_krw:,}원"
             )
+            notify_buy(ticker, current, amount, order_krw)
             return True
         except Exception as e:
             logger.error(f"매수 예외 {ticker}: {e}")
+            notify_error(f"매수 실패 {ticker}: {e}")
             return False
 
 
@@ -106,10 +109,12 @@ def sell(ticker: str, reason: str = "") -> bool:
                 f"[매도] {ticker} @ {current:,.0f}원 | "
                 f"수익률={pnl:+.1f}% | 사유={reason}"
             )
+            notify_sell(ticker, current, pnl, reason)
             del _positions[ticker]
             return True
         except Exception as e:
             logger.error(f"매도 예외 {ticker}: {e}")
+            notify_error(f"매도 실패 {ticker}: {e}")
             return False