Fix dark mode prose text color in card descriptions

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/app.css

@@ -114,6 +114,9 @@ html.dark {
 	--color-warning: #eab308;
 }
 
+.dark .prose {
+	color: #e5e7eb;
+}
 .dark .prose code {
 	background: #374151;
 	color: #e5e7eb;