Modernize collaborative pixel art platform to production-ready architecture

Major refactor from simple HTML/JS app to modern full-stack TypeScript application:

## Architecture Changes
- Migrated to monorepo structure with workspaces (backend, frontend, shared)
- Backend: Node.js + Express + TypeScript + Socket.IO
- Frontend: Next.js 15.5 + React 19 + TypeScript + Tailwind CSS
- Shared: Common types and utilities across packages

## Key Features Implemented
- Real-time WebSocket collaboration via Socket.IO
- Virtual canvas with chunked loading for performance
- Modern UI with dark mode and responsive design
- Mock database system for easy development (Redis/PostgreSQL compatible)
- Comprehensive error handling and rate limiting
- User presence and cursor tracking
- Infinite canvas support with zoom/pan controls

## Performance Optimizations
- Canvas virtualization - only renders visible viewport
- Chunked pixel data loading (64x64 pixel chunks)
- Optimized WebSocket protocol
- Memory-efficient state management with Zustand

## Development Experience
- Full TypeScript support across all packages
- Hot reload for both frontend and backend
- Docker support for production deployment
- Comprehensive linting and formatting
- Automated development server startup

## Fixed Issues
- Corrected start script paths
- Updated environment configuration
- Fixed ESLint configuration issues
- Ensured all dependencies are properly installed
- Verified build process works correctly

frontend/package.json

@@ -0,0 +1,35 @@
+{
+  "name": "@gaplace/frontend",
+  "version": "0.1.0",
+  "private": true,
+  "scripts": {
+    "dev": "next dev",
+    "build": "next build",
+    "start": "next start",
+    "lint": "next lint",
+    "type-check": "tsc --noEmit"
+  },
+  "dependencies": {
+    "@gaplace/shared": "file:../shared",
+    "next": "^15.5.0",
+    "react": "^19.1.1",
+    "react-dom": "^19.1.1",
+    "socket.io-client": "^4.8.1",
+    "zustand": "^5.0.2",
+    "@tanstack/react-query": "^5.62.8",
+    "framer-motion": "^11.15.0",
+    "tailwindcss": "^3.4.17",
+    "autoprefixer": "^10.4.20",
+    "postcss": "^8.5.4",
+    "clsx": "^2.1.1",
+    "tailwind-merge": "^2.5.6"
+  },
+  "devDependencies": {
+    "typescript": "^5.7.3",
+    "@types/node": "^22.10.6",
+    "@types/react": "^19.0.2",
+    "@types/react-dom": "^19.0.2",
+    "eslint": "^8.57.1",
+    "eslint-config-next": "^15.5.0"
+  }
+}