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/notify.py

@@ -0,0 +1,51 @@
+"""Telegram 매매 알림."""
+
+from __future__ import annotations
+
+import logging
+import os
+
+import requests
+
+logger = logging.getLogger(__name__)
+
+_TOKEN = os.getenv("TELEGRAM_TRADE_TOKEN", "")
+_CHAT_ID = os.getenv("TELEGRAM_CHAT_ID", "")
+_API = "https://api.telegram.org/bot{token}/sendMessage"
+
+
+def _send(text: str) -> None:
+    if not _TOKEN or not _CHAT_ID:
+        logger.warning("Telegram 설정 없음, 알림 스킵")
+        return
+    try:
+        requests.post(
+            _API.format(token=_TOKEN),
+            json={"chat_id": _CHAT_ID, "text": text, "parse_mode": "HTML"},
+            timeout=5,
+        )
+    except Exception as e:
+        logger.error(f"Telegram 알림 실패: {e}")
+
+
+def notify_buy(ticker: str, price: float, amount: float, invested_krw: int) -> None:
+    _send(
+        f"📈 <b>[매수]</b> {ticker}\n"
+        f"가격: {price:,.0f}원\n"
+        f"수량: {amount}\n"
+        f"투자금: {invested_krw:,}원"
+    )
+
+
+def notify_sell(ticker: str, price: float, pnl_pct: float, reason: str) -> None:
+    emoji = "✅" if pnl_pct >= 0 else "🔴"
+    _send(
+        f"{emoji} <b>[매도]</b> {ticker}\n"
+        f"가격: {price:,.0f}원\n"
+        f"수익률: {pnl_pct:+.1f}%\n"
+        f"사유: {reason}"
+    )
+
+
+def notify_error(message: str) -> None:
+    _send(f"⚠️ <b>[오류]</b>\n{message}")