feat(center-nodes): add node status model and status update endpoint

Fabric.Backend.Center/src/entities/guild-node.entity.ts

@@ -14,8 +14,12 @@ export class GuildNode {
   @Column()
   endpoint!: string;
 
-  @Column({ default: 'active' })
-  status!: string;
+  @Column({
+    type: 'enum',
+    enum: ['active', 'offline', 'revoked'],
+    default: 'active',
+  })
+  status!: 'active' | 'offline' | 'revoked';
 
   @CreateDateColumn()
   createdAt!: Date;