feat(web): add Next.js portfolio with live MT5 dashboard

- Linear design system (dark canvas, lavender accent)
- Live account stats, open positions, pending orders (30s polling)
- Trade history with equity curve chart
- Backtest results table
- Proxy API routes — MT5_BASE_URL server-side only, never exposed to browser
- Deploy on Vercel: set MT5_BASE_URL env var

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

web/tsconfig.json

@@ -0,0 +1,40 @@
+{
+  "compilerOptions": {
+    "lib": [
+      "dom",
+      "dom.iterable",
+      "esnext"
+    ],
+    "allowJs": true,
+    "skipLibCheck": true,
+    "strict": true,
+    "noEmit": true,
+    "esModuleInterop": true,
+    "module": "esnext",
+    "moduleResolution": "bundler",
+    "resolveJsonModule": true,
+    "isolatedModules": true,
+    "jsx": "preserve",
+    "incremental": true,
+    "plugins": [
+      {
+        "name": "next"
+      }
+    ],
+    "paths": {
+      "@/*": [
+        "./*"
+      ]
+    },
+    "target": "ES2017"
+  },
+  "include": [
+    "next-env.d.ts",
+    "**/*.ts",
+    "**/*.tsx",
+    ".next/types/**/*.ts"
+  ],
+  "exclude": [
+    "node_modules"
+  ]
+}