fix: 保持瀑布流空图片为正方形

src/features/subject-images/SubjectImagesPage.vue

@@ -700,6 +700,7 @@ const rules = { concurrency: integerRule('批量并发'), limit: integerRule('
                     <AssetImage
                         :src="coverImage(form)?.imageUrl"
                         :alt="`${form.subject.name} · ${form.name}`"
+                        :class="{ 'form-image-has-source': Boolean(coverImage(form)?.imageUrl) }"
                         :object-fit="layout === 'masonry' ? 'contain' : 'cover'"
                         preview
                         :empty-text="hasRunningImages(form.images) ? '后台正在生成图片' : '尚未生成图片'"
@@ -844,10 +845,13 @@ const rules = { concurrency: integerRule('批量并发'), limit: integerRule('
     grid-row-end: span var(--form-image-row-span, 1);
 }
 .form-image-masonry .asset-image {
+    aspect-ratio: 1 / 1;
+}
+.form-image-masonry .asset-image.form-image-has-source {
     @apply aspect-auto;
 }
-.form-image-masonry .asset-image .n-image,
-.form-image-masonry .asset-image .n-image img {
+.form-image-masonry .asset-image.form-image-has-source .n-image,
+.form-image-masonry .asset-image.form-image-has-source .n-image img {
     @apply h-auto;
 }
 .gallery-sticky-controls > .form-image-filter-region {