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/entities/map-library.entity.ts

@@ -0,0 +1,46 @@
+import { Entity, PrimaryGeneratedColumn, Column, ManyToOne, JoinColumn, Check } from 'typeorm';
+import { License } from './license.entity';
+
+@Entity('map_library')
+@Check(`"map_type" IN ('custom', 'procedural')`)
+export class MapLibrary {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column({ type: 'uuid' })
+  license_id: string;
+
+  @Column({ type: 'varchar', length: 255 })
+  filename: string;
+
+  @Column({ type: 'varchar', length: 255 })
+  display_name: string;
+
+  @Column({ type: 'text' })
+  storage_path: string;
+
+  @Column({ type: 'bigint', default: 0 })
+  file_size_bytes: number;
+
+  @Column({ type: 'varchar', length: 20, default: 'custom' })
+  map_type: string;
+
+  @Column({ type: 'integer', nullable: true })
+  seed: number | null;
+
+  @Column({ type: 'integer', nullable: true })
+  world_size: number | null;
+
+  @Column({ type: 'text', nullable: true })
+  thumbnail_path: string | null;
+
+  @Column({ type: 'varchar', length: 64 })
+  checksum: string;
+
+  @Column({ type: 'timestamptz', default: () => 'NOW()' })
+  uploaded_at: Date;
+
+  @ManyToOne(() => License, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'license_id' })
+  license: License;
+}