add option to indicate image copyright for summary preview

lib/summary.typ

@@ -23,10 +23,12 @@
     }
 
     summary-card-preview {
-      display: block;
+      display: flex;
+      flex-direction: column;
       width: 100%;
 
       img {
+        display: block;
         width: 100%;
         height: 100%;
         object-fit: contain;
@@ -54,9 +56,12 @@
   }
   ```
   chtml.summary-card({
-      chtml.summary-card-preview(
+      chtml.summary-card-preview({
         html.a(href: summ.template-args.url, summ.preview-image)
-      )
+        if summ.img-copyright != none {
+          html.small[Image: #sym.copyright #summ.img-copyright]
+        }
+      })
       chtml.summary-card-description({
         heading(level: 2, html.a(href: summ.template-args.url, summ.document-args.title))
 
@@ -79,6 +84,8 @@
   /// Right now, this cannot be used for link preview because open graph expect an url for the image, and typst inline
   /// the images directly in the html file in base64.
   preview-image: none,
+  /// The copyright for the image 
+  img-copyright: none,
   /// The author or authors of the page
   author: none,
   /// A description of the page
@@ -104,6 +111,7 @@
       url: url,
     ),
     preview-image: preview-image,
+    img-copyright: img-copyright,
     card: []
   )
   summ.card = gen_summary_card(summ)

test_template/main.typ

@@ -172,6 +172,7 @@ thead {
       url: "http://test.example.com",
       title: "Card " + str(perm.at(i)),
       preview-image: summ.preview-image,
+      img-copyright: if calc.rem(i, 3) == 0 { [Histausse ] } else { none },
       author: "Me!",
       description: lorem(10 * calc.rem(i * 123,  10)),
       date: datetime(year: 2000, month: 12, day: perm.at(i)),