Add Hono backend with PostgreSQL, auth, cloud saves, and leaderboard

Server app (apps/server) with Hono framework and Drizzle ORM:
- PostgreSQL schema: users, saves, leaderboard, achievements tables
- Anonymous auth with UUID tokens, optional email/password linking
- Cloud save API: list, get, upsert, delete with auto-save hook
- Leaderboard API: per-category rankings with score submission
- CORS configured for dev server ports
- Typed middleware with Hono env variables

Frontend cloud save integration:
- API client with auth token management in localStorage
- useCloudSave hook auto-saves every 300 ticks when authenticated
- Vite env type declarations for VITE_API_URL

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

packages/tsconfig/node.json

@@ -2,6 +2,7 @@
   "extends": "./base.json",
   "compilerOptions": {
     "lib": ["ES2022"],
+    "types": ["node"],
     "module": "ESNext",
     "outDir": "dist",
     "rootDir": "src"