fix: filter replies from public/local/hashtag timelines (Mastodon behavior)

lib/mastodon/routes/timelines.js

@@ -102,9 +102,10 @@ router.get("/api/v1/timelines/public", async (req, res, next) => {
     const baseUrl = `${req.protocol}://${req.get("host")}`;
     const limit = parseLimit(req.query.limit);
 
-    // Public timeline: only public visibility, no context items
+    // Public timeline: only public visibility, no context items, no replies
     const baseFilter = {
       isContext: { $ne: true },
+      inReplyTo: { $exists: false },
       visibility: "public",
     };
 
@@ -204,6 +205,7 @@ router.get("/api/v1/timelines/tag/:hashtag", async (req, res, next) => {
 
     const baseFilter = {
       isContext: { $ne: true },
+      inReplyTo: { $exists: false },
       visibility: { $in: ["public", "unlisted"] },
       category: hashtag,
     };