fix: reply sort direction now follows the comment sort pill (descending param)

Replies within a comment thread were always sorted ascending regardless of
the descending parameter. Now they respect it, matching root comment sort.

app/src/main/java/ai/multica/app/FeatureSyncHelpers.java

@@ -200,7 +200,9 @@ final class IssueCommentThreads {
         ArrayList<Thread> threads = new ArrayList<>();
         for (Models.Comment root : roots) {
             ArrayList<Models.Comment> replies = repliesByRoot.getOrDefault(clean(root.id), new ArrayList<>());
-            replies.sort(IssueCommentThreads::compareCreatedAt);
+            replies.sort((left, right) -> descending
+                    ? compareCreatedAt(right, left)
+                    : compareCreatedAt(left, right));
             threads.add(new Thread(root, replies));
         }
         return threads;