docs: add CLAUDE.md for development guidance and project architecture overview

CLAUDE.md

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+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Development Commands
+
+### Core Commands
+- **Run development server**: `npm run dev:server` - Starts the server with hot reload using tsx watch
+- **Build project**: `npm run build` - Runs TypeScript check and builds with tsup
+- **Start production**: `npm run start:prod` - Runs the compiled application from dist/
+- **Lint code**: `npm run lint` - Runs ESLint with auto-fix on TypeScript files
+- **Check lint**: `npm run lint:check` - Runs ESLint without auto-fix
+
+### Database Commands
+The project uses Prisma with support for multiple database providers (PostgreSQL, MySQL, psql_bouncer). Commands automatically use the DATABASE_PROVIDER from .env:
+
+- **Generate Prisma client**: `npm run db:generate`
+- **Deploy migrations**: `npm run db:deploy` (Unix/Mac) or `npm run db:deploy:win` (Windows)
+- **Open Prisma Studio**: `npm run db:studio`
+- **Create new migration**: `npm run db:migrate:dev` (Unix/Mac) or `npm run db:migrate:dev:win` (Windows)
+
+## Architecture Overview
+
+### Project Structure
+Evolution API is a WhatsApp integration platform built with TypeScript and Express, supporting both Baileys (WhatsApp Web) and WhatsApp Cloud API connections.
+
+### Core Components
+
+**API Layer** (`src/api/`)
+- **Controllers**: Handle HTTP requests for different resources (instance, chat, group, sendMessage, etc.)
+- **Services**: Business logic layer containing auth, cache, channel, monitor, proxy services
+- **Routes**: RESTful API endpoints with authentication guards
+- **DTOs**: Data transfer objects for request/response validation using class-validator
+- **Repository**: Database access layer using Prisma ORM
+
+**Integrations** (`src/api/integrations/`)
+- **Chatbot**: Supports multiple chatbot platforms (Typebot, Chatwoot, Dify, OpenAI, Flowise, N8N)
+- **Event**: WebSocket, RabbitMQ, Amazon SQS event systems
+- **Storage**: S3/Minio file storage integration
+- **Channel**: Multi-channel messaging support
+
+**Configuration** (`src/config/`)
+- Environment configuration management
+- Database provider switching (PostgreSQL/MySQL/PgBouncer)
+- Multi-tenant support via DATABASE_CONNECTION_CLIENT_NAME
+
+### Key Design Patterns
+
+1. **Multi-Provider Database**: Uses `runWithProvider.js` to dynamically select database provider and migrations
+2. **Module System**: Path aliases configured in tsconfig.json (@api, @cache, @config, @utils, @validate)
+3. **Event-Driven**: EventEmitter2 for internal events, supports multiple external event systems
+4. **Instance Management**: Each WhatsApp connection is managed as an instance with memory lifecycle (DEL_INSTANCE config)
+
+### Database Schema
+- Supports multiple providers with provider-specific schemas in `prisma/`
+- Separate migration folders for each provider (postgresql-migrations, mysql-migrations)
+- psql_bouncer uses PostgreSQL migrations but with connection pooling
+
+### Authentication & Security
+- JWT-based authentication
+- API key support
+- Instance-specific authentication
+- Configurable CORS settings
+
+### Messaging Features
+- WhatsApp Web (Baileys library) and WhatsApp Cloud API support
+- Message queue support (RabbitMQ, SQS)
+- Real-time updates via WebSocket
+- Media file handling with S3/Minio storage
+- Multiple chatbot integrations with trigger management
+
+### Environment Variables
+Critical configuration in `.env`:
+- SERVER_TYPE, SERVER_PORT, SERVER_URL
+- DATABASE_PROVIDER and DATABASE_CONNECTION_URI
+- Log levels and Baileys-specific logging
+- Instance lifecycle management (DEL_INSTANCE)
+- Feature toggles for data persistence (DATABASE_SAVE_*)