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>

turbo.json

@@ -0,0 +1,20 @@
+{
+  "$schema": "https://turbo.build/schema.json",
+  "tasks": {
+    "build": {
+      "dependsOn": ["^build"],
+      "outputs": ["dist/**"]
+    },
+    "dev": {
+      "cache": false,
+      "persistent": true
+    },
+    "typecheck": {
+      "dependsOn": ["^build"]
+    },
+    "lint": {},
+    "clean": {
+      "cache": false
+    }
+  }
+}