Declare cards-list container on RecentDownloads

GCard's responsive width rules use `@container cards-list (max-width: ...)`
to drop cards from 1/3 width to 1/2 / full width on narrow viewports.
RecentDownloads.vue had no `container: cards-list / inline-size`
declaration anywhere up the tree, so those queries never fired and
cards stayed at `calc(100% / 3)` regardless of viewport width — which,
combined with the recently fixed title squashing, was producing
per-syllable title wrapping in the export card on narrow screens.

Match the idiom used by WorkflowCardList and HistoryCardList.

client/src/components/Downloads/RecentDownloads.vue

@@ -91,3 +91,9 @@ const breadcrumbItems = [{ title: "Recent Exports & Downloads", to: "/downloads"
         </div>
     </div>
 </template>
+
+<style lang="scss" scoped>
+.recent-downloads {
+    container: cards-list / inline-size;
+}
+</style>