feat: Add backend support for one-click Rust server deployment

Add deploy endpoint, DTO, NATS command publisher, and WebSocket bridge
subscription to support the one-click server deployment feature via the
companion agent.

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

backend-nest/src/modules/servers/servers.service.ts

@@ -5,6 +5,7 @@ import { ServerConnection } from '../../entities/server-connection.entity';
 import { ServerConfig } from '../../entities/server-config.entity';
 import { NatsService } from '../../services/nats.service';
 import { UpdateServerConfigDto } from './dto/update-config.dto';
+import { DeployServerDto } from './dto/deploy-server.dto';
 
 @Injectable()
 export class ServersService {
@@ -86,4 +87,12 @@ export class ServersService {
     await this.natsService.sendServerCommand(licenseId, 'restart');
     return { message: 'Restart command sent' };
   }
+
+  /**
+   * Deploy Rust server via companion agent
+   */
+  async deployServer(licenseId: string, dto: DeployServerDto) {
+    await this.natsService.sendDeployCommand(licenseId, { ...dto });
+    return { message: 'Deployment started' };
+  }
 }