feat: autonomous trading engine — full implementation

- Database migration 018 with 13 tables for trading engine state
- Trading engine service (services/trading/) with 12 pure computation modules:
  position sizer, stop-loss manager, reserve pool, circuit breaker,
  risk tier controller, correlation matrix, tax lots, trading window,
  gradual entry, notifications, micro-trading, backtester
- Core TradingEngine with pre-trade evaluation pipeline and integration wiring
- FastAPI HTTP service with 14 endpoints (health, config, decisions, metrics, backtest)
- Performance tracker with Sharpe ratio, drawdown, profit factor computation
- 194 Python tests (165 property-based + 29 integration)
- Frontend: 13 TanStack Query hooks, 7 dashboard panels, tabbed Trading Engine page
- Helm chart entry, network policy, nginx proxy, ingress for trading-engine
- Shared infrastructure: enums, Redis keys, TradingConfig in AppConfig

frontend/src/components/AppLayout.tsx

@@ -17,6 +17,7 @@ import {
   LayoutDashboard,
   List,
   Globe,
+  BarChart3,
 } from 'lucide-react';
 
 interface NavItem {
@@ -37,6 +38,7 @@ const navItems: NavItem[] = [
   { to: '/orders', label: 'Orders', icon: <ShoppingCart size={18} />, group: 'Trading' },
   { to: '/positions', label: 'Positions', icon: <Wallet size={18} />, group: 'Trading' },
   { to: '/trading', label: 'Trading Controls', icon: <ShieldCheck size={18} />, group: 'Trading' },
+  { to: '/trading/engine', label: 'Trading Engine', icon: <BarChart3 size={18} />, group: 'Trading' },
   { to: '/ops/pipeline', label: 'Pipeline', icon: <Activity size={18} />, group: 'Ops' },
   { to: '/ops/ingestion', label: 'Ingestion', icon: <Download size={18} />, group: 'Ops' },
   { to: '/ops/model', label: 'Model Perf', icon: <Cpu size={18} />, group: 'Ops' },