feat: Add Backtest to navigation

frontend/src/components/Layout.tsx

@@ -1,5 +1,5 @@
 import { Link, useLocation } from 'react-router-dom'
-import { LayoutDashboard, History, Cpu, Activity, SlidersHorizontal } from 'lucide-react'
+import { LayoutDashboard, History, Cpu, Activity, SlidersHorizontal, BarChart3 } from 'lucide-react'
 import { useQuery } from '@tanstack/react-query'
 import api from '../lib/api'
 import { useWebSocket } from '../hooks/useWebSocket'
@@ -21,6 +21,7 @@ const Layout = ({ children }: LayoutProps) => {
     const navItems = [
         { path: '/', icon: LayoutDashboard, label: '대시보드' },
         { path: '/strategy', icon: SlidersHorizontal, label: '전략 설정' },
+        { path: '/backtest', icon: BarChart3, label: '백테스트' },
         { path: '/trades', icon: History, label: '매매 로그' },
         { path: '/mcp', icon: Cpu, label: 'MCP 상태' },
     ]