add: stacks mode and sort

crates/core/src/database/messages.rs

@@ -157,6 +157,15 @@ impl DataManager {
                         return Err(Error::NotAllowed);
                     }
 
+                    // check if the user can read the channel
+                    let membership = self
+                        .get_membership_by_owner_community(user.id, channel.community)
+                        .await?;
+
+                    if !channel.check_read(user.id, Some(membership.role)) {
+                        continue;
+                    }
+
                     // create notif
                     self.create_notification(Notification::new(
                         "You've been mentioned in a message!".to_string(),