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/config/configuration.ts

@@ -0,0 +1,42 @@
+export default () => ({
+  port: parseInt(process.env.API_PORT || '3000', 10),
+  database: {
+    url: process.env.DATABASE_URL || 'postgres://corrosion:corrosion_dev@localhost:5432/corrosion',
+    maxConnections: parseInt(process.env.DATABASE_MAX_CONNECTIONS || '20', 10),
+  },
+  nats: {
+    url: process.env.NATS_URL || 'nats://localhost:4222',
+  },
+  jwt: {
+    secret: process.env.JWT_SECRET || 'change-me',
+    accessExpirySeconds: parseInt(process.env.JWT_ACCESS_EXPIRY_SECONDS || '900', 10),
+    refreshExpirySeconds: parseInt(process.env.JWT_REFRESH_EXPIRY_SECONDS || '604800', 10),
+  },
+  encryption: {
+    key: process.env.ENCRYPTION_KEY || '',
+  },
+  admin: {
+    email: process.env.ADMIN_EMAIL || '',
+    password: process.env.ADMIN_PASSWORD || '',
+    username: process.env.ADMIN_USERNAME || 'Commander',
+    licenseKey: process.env.ADMIN_LICENSE_KEY || '',
+  },
+  cloudflare: {
+    apiToken: process.env.CLOUDFLARE_API_TOKEN || '',
+    zoneId: process.env.CLOUDFLARE_ZONE_ID || '',
+    baseDomain: process.env.BASE_DOMAIN || 'corrosionmgmt.com',
+  },
+  steam: {
+    apiKey: process.env.STEAM_API_KEY || '',
+  },
+  smtp: {
+    host: process.env.SMTP_HOST || '',
+    port: parseInt(process.env.SMTP_PORT || '587', 10),
+    username: process.env.SMTP_USERNAME || '',
+    password: process.env.SMTP_PASSWORD || '',
+    from: process.env.SMTP_FROM || 'noreply@corrosionmgmt.com',
+  },
+  frontend: {
+    url: process.env.FRONTEND_URL || 'http://localhost:5174',
+  },
+});