Fix status page crash

src/routes/timeline.nim

@@ -100,7 +100,7 @@ proc createTimelineRouter*(cfg: Config) =
 
       let conversation = await getTweet(@"name", @"id", getAgent())
       if conversation == nil or conversation.tweet.id.len == 0:
-        if conversation.tweet.tombstone.len > 0:
+        if conversation != nil and conversation.tweet.tombstone.len > 0:
           resp Http404, showError(conversation.tweet.tombstone, cfg.title)
         else:
           resp Http404, showError("Tweet not found", cfg.title)