Agregar campo username a User entity y DTO

- Columna username (unique, nullable) en auth.users
- Campo username en CreateUserDto y UpdateUserDto

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/modules/trips/dto/update-trip.dto.ts

@@ -0,0 +1,16 @@
+import { PartialType } from '@nestjs/swagger';
+import { CreateTripDto, CreateTripDayDto, CreateTripActivityDto } from './create-trip.dto';
+import { ApiPropertyOptional } from '@nestjs/swagger';
+import { IsEnum, IsOptional } from 'class-validator';
+import { TripStatus } from '../../../entities/user-trip.entity';
+
+export class UpdateTripDto extends PartialType(CreateTripDto) {
+  @ApiPropertyOptional({ description: 'Trip status', enum: TripStatus })
+  @IsOptional()
+  @IsEnum(TripStatus)
+  status?: TripStatus;
+}
+
+export class UpdateTripDayDto extends PartialType(CreateTripDayDto) {}
+
+export class UpdateTripActivityDto extends PartialType(CreateTripActivityDto) {}