Set up PostgreSQL database configuration and enhance application structure

- Added .env.example with database connection details and JWT configuration.
- Introduced docker-compose.yml for PostgreSQL service setup with health checks.
- Created drizzle.config.ts for database schema and migration management.
- Updated nest-cli.json to include Swagger plugin configuration for API documentation.
- Enhanced package.json with new database-related scripts and dependencies.
- Implemented initial database migrations for user and token management.
- Configured application bootstrap process to load environment variables and set up Swagger.
- Added shared application configuration in configure-app.ts for consistent setup.
- Included unit tests for application configuration and Swagger setup.

.cursor/rules/nestjs-swagger.mdc

@@ -0,0 +1,56 @@
+---
+description: NestJS OpenAPI/Swagger conventions for controllers and DTOs
+globs: "src/**/*.controller.ts,src/**/dto/**/*.ts,src/common/swagger/**/*.ts,src/main.ts,nest-cli.json"
+alwaysApply: false
+---
+
+# NestJS Swagger Best Practices
+
+## Controllers
+
+Document every HTTP handler:
+
+```typescript
+@ApiTags('auth')
+@Controller('auth')
+export class AuthController {
+  @Post('login')
+  @ApiOperation({ summary: 'Log in' })
+  @ApiOkResponse({ type: TokenPairDto })
+  login(@Body() dto: LoginDto) { /* ... */ }
+
+  @Get('me')
+  @ApiBearerAuth('access-token')
+  @ApiOkResponse({ type: MeResponseDto })
+  me(@CurrentUser() user: AuthUser) { /* ... */ }
+}
+```
+
+- Use `@ApiTags`, `@ApiOperation`, and typed `@ApiOkResponse` / `@ApiCreatedResponse` / `@ApiNoContentResponse`
+- Response types must be DTO **classes**, not interfaces or domain entities
+- Add `@ApiBearerAuth('access-token')` only on JWT-protected routes
+- Public (`@Public()`) routes must omit bearer auth
+- Document expected errors (`@ApiBadRequestResponse`, `@ApiUnauthorizedResponse`, etc.) when meaningful
+
+## DTOs
+
+- Request and response DTOs live under `dto/`
+- Never expose domain entities or sensitive fields (`passwordHash`, secrets) in OpenAPI
+- Nest CLI Swagger plugin is enabled — use `@ApiProperty` for examples, `format: 'password'`, `writeOnly`, not to restate every class-validator rule
+- Examples must be fake; never real tokens or secrets
+
+```typescript
+// BAD — documents entity / real secret
+@ApiOkResponse({ type: User })
+@ApiProperty({ example: process.env.JWT_ACCESS_SECRET })
+
+// GOOD — response DTO + fake example
+@ApiOkResponse({ type: MeResponseDto })
+@ApiProperty({ example: 'alice', format: 'password', writeOnly: true })
+```
+
+## Bootstrap
+
+- Mount UI at `/docs` and JSON at `/docs-json` only (via `setupSwagger` / `configureApp`)
+- Swagger is off when `NODE_ENV=production` unless `SWAGGER_ENABLED=true`
+- Keep the `@nestjs/swagger` plugin in `nest-cli.json` (`classValidatorShim`, `introspectComments`, `dtoFileNameSuffix: [".dto.ts"]`)