Initial scaffold: AI Tycoon monorepo with core game loop

Turborepo monorepo with three packages:
- packages/shared: TypeScript types for all 14 game systems + balance constants + formatting utils
- packages/game-engine: Pure TS simulation engine with tick processor, economy, infrastructure, compute, research, market, and reputation systems
- apps/web: React + Vite + Tailwind + Zustand frontend with sidebar dashboard layout, new game screen, dashboard with charts, infrastructure management, and model training pages

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

apps/web/src/App.tsx

@@ -0,0 +1,15 @@
+import { useGameStore } from '@/store';
+import { MainLayout } from '@/components/layout/MainLayout';
+import { NewGameScreen } from '@/components/game/NewGameScreen';
+import { useGameLoop } from '@/hooks/useGameLoop';
+
+export function App() {
+  const companyName = useGameStore((s) => s.meta.companyName);
+  useGameLoop();
+
+  if (!companyName) {
+    return <NewGameScreen />;
+  }
+
+  return <MainLayout />;
+}