feat: initialize Annual Gala Interactive System monorepo

- Set up pnpm workspace with 4 packages: shared, server, client-mobile, client-screen
- Implement Redis atomic voting with Lua scripts (HINCRBY + distributed lock)
- Add optimistic UI with IndexedDB queue for offline resilience
- Configure Socket.io with auto-reconnection (infinite retries)
- Separate mobile (Vant) and big screen (Pixi.js) dependencies

Tech stack:
- Frontend Mobile: Vue 3 + Vant + Socket.io-client
- Frontend Screen: Vue 3 + Pixi.js + GSAP
- Backend: Express + Socket.io + Redis + Prisma/MySQL

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/server/.env.example

@@ -0,0 +1,21 @@
+# Server Environment Variables
+
+# Server
+PORT=3000
+NODE_ENV=development
+
+# CORS (comma-separated origins)
+CORS_ORIGINS=http://localhost:5173,http://localhost:5174
+
+# Redis
+REDIS_HOST=localhost
+REDIS_PORT=6379
+REDIS_PASSWORD=
+REDIS_DB=0
+
+# MySQL (Prisma)
+DATABASE_URL="mysql://root:password@localhost:3306/gala"
+
+# JWT
+JWT_SECRET=your-super-secret-jwt-key-change-in-production
+JWT_EXPIRES_IN=24h