feat: sort dms by latest message (#543)

cmd/guilds_tree.go

@@ -211,6 +211,16 @@ func (gt *GuildsTree) onSelected(n *tview.TreeNode) {
 			return
 		}
 
+	        sort.Slice(cs, func(a, b int) bool {
+	                msgID := func(ch discord.Channel) discord.MessageID {
+	         	    if ch.LastMessageID.IsValid() {
+	                	return ch.LastMessageID
+	            	    }
+	            	    return discord.MessageID(ch.ID)
+	               }
+	               return msgID(cs[a]) > msgID(cs[b])
+	        })
+
 		for _, c := range cs {
 			gt.createChannelNode(n, c)
 		}