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>

packages/shared/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "@ai-tycoon/shared",
+  "private": true,
+  "version": "0.0.1",
+  "type": "module",
+  "main": "./src/index.ts",
+  "types": "./src/index.ts",
+  "scripts": {
+    "typecheck": "tsc --noEmit"
+  },
+  "devDependencies": {
+    "@ai-tycoon/tsconfig": "workspace:*",
+    "typescript": "^5.8.0"
+  }
+}