seed-loader: 多值 lookup（multiple: true）的自然键数组被静默丢弃，记录落库但整个关联字段缺失 #3911

// author.object.ts
export const Author = ObjectSchema.create({
  name: 'author',
  fields: { name: Field.text({ label: 'Name', required: true }) },
});

// book.object.ts
export const Book = ObjectSchema.create({
  name: 'book',
  fields: {
    name: Field.text({ label: 'Title', required: true }),
    authors: Field.lookup('author', { label: 'Authors', multiple: true }),
  },
});

// seeds
const authors = defineSeed(Author, {
  mode: 'upsert', externalId: 'name',
  records: [{ name: 'Alice' }, { name: 'Bob' }],
});
const books = defineSeed(Book, {
  mode: 'upsert', externalId: 'name',
  records: [{ name: 'Refactoring', authors: ['Alice', 'Bob'] }],
});