feat: Complete NestJS backend scaffold — 22 modules, 39 entities, WebSocket gateway

Full backend rewrite from Rust/Axum to NestJS/TypeScript.
- 22 feature modules (auth, servers, wipes, maps, plugins, players, console,
  chat, team, notifications, settings, schedules, analytics, alerts, status,
  store, webstore, admin, setup, migration, users, licenses)
- 39 TypeORM entities matching PostgreSQL schema (12 migrations)
- Common infrastructure: JWT/RBAC guards, decorators, exception filter
- NATS service with pub/sub/request-reply
- Socket.IO WebSocket gateway with NATS bridge
- Docker: NestJS Dockerfile + updated docker-compose.yml
- Zero compile errors (npx tsc --noEmit clean)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend-nest/src/modules/chat/dto/flag-message.dto.ts

@@ -0,0 +1,13 @@
+import { IsBoolean, IsOptional, IsString } from 'class-validator';
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+
+export class FlagMessageDto {
+  @ApiProperty({ example: true, description: 'Whether to flag or unflag the message' })
+  @IsBoolean()
+  flagged: boolean;
+
+  @ApiPropertyOptional({ example: 'Inappropriate language', description: 'Reason for flagging' })
+  @IsOptional()
+  @IsString()
+  flag_reason?: string;
+}