feat: trading bot MVP — ICT Order Block + Liquidity Sweep strategy

Full-stack trading bot with:
- FastAPI backend with ICT strategy (Order Block + Liquidity Sweep detection)
- Backtester engine with rolling window, spread simulation, and performance metrics
- Hybrid market data service (yfinance + TwelveData with rate limiting + SQLite cache)
- Simulated exchange for paper trading
- React/TypeScript frontend with TradingView lightweight-charts v5
- Live dashboard with candlestick chart, OHLC legend, trade markers
- Backtest page with configurable parameters, equity curve, and trade table
- WebSocket support for real-time updates
- Bot runner with asyncio loop for automated trading

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

backend/requirements.txt

@@ -0,0 +1,11 @@
+fastapi==0.115.6
+uvicorn[standard]==0.32.1
+pandas==2.2.3
+sqlalchemy[asyncio]==2.0.36
+aiosqlite==0.20.0
+pydantic-settings==2.6.1
+python-dotenv==1.0.1
+httpx==0.27.2
+websockets==13.1
+python-multipart==0.0.18
+yfinance==0.2.48