v2.2.2 - Update README Documentation

📝 Documentation

• Fix tech stack versions: Hono.js v3 → v4, Zod v3 → v4
• Add docs/ folder to project structure
• Add Swagger UI & OpenAPI section (/docs, /docs/json)
• Update Health Check response version to 2.1.0
• Add status field to create user body example
• Clarify that /api/users does not support ?search param