🐛 Fix card thumbnail clipping on narrow grid columns

Remove the obsolete min-width on thumbnail_card, a leftover from the
old fixed-size background thumbnail, so images shrink with the card
and object-cover crops them centered instead of clipping the right
side once columns drop below 300px.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

assets/css/compiled/main.css

@@ -4164,7 +4164,6 @@ pre {
   height: 100%;
 }
 .thumbnail_card {
-  min-width: 300px;
   aspect-ratio: var(--thumbnail-aspect-ratio, 1.5);
   height: auto;
 }

assets/css/main.css

@@ -182,7 +182,6 @@ pre {
 }
 
 .thumbnail_card {
-  min-width: 300px;
   aspect-ratio: var(--thumbnail-aspect-ratio, 1.5);
   height: auto;
 }