backend-dev-guidelines

# Backend Development Guidelines ## NestJS Layered Architecture ``` src/ ├── modules/ │ └── users/ │ ├── users.module.ts # DI wiring │ ├── users.controller.ts # HTTP layer — parse, validate, delegate │ ├── users.service.ts # Business logic │ ├── users.repository.ts # Data access │ ├── dto/ │ │ ├── create-user.dto.ts │ │ └── update-user.dto.ts │ ├── entities/ │ │ └── user.entity.ts │ └── users.spec.ts ├── common/ │ ├── filters/ # Global exception filters │ ├── guards/ # Auth/RBAC guards │ ├── interceptors/ # Logging, transform │ ├── decorators/ # Custom decorators │ └── pipes/ # Validation pipes └── config/ └── configuration.ts ``` ## Controller Layer Controllers should be thin: validate inputs, call services, return responses. ```typescript // users/users.controller.ts import { Controller, Get, Post, Put, Delete, Body, Param, Query, ParseIntPipe, UseGuards, HttpCode, HttpStatus, } from '@nestjs/common' import { ApiTags, ApiOperation, ApiBearerAuth } from '@nestjs/swagger' import { JwtAuthGuard } from '../common/guards/jwt-auth.guard' import { CurrentUser } from '../common/decorators/current-user.decorator' import { UsersService } from './users.service' import { CreateUserDto } from './dto/create-user.dto' import { UpdateUserDto } from './dto/update-user.dto' import { Pagina...