Notes:
-
Not truly persistent. Will be cleared on a restart.
-
The notification icon is now in a poor place if you have the side panel hidden and there is no way to move it back to the top view bar WHERE IT BELONGS
An alternative could be to use the file notifications integration. Displaying the file contents in lovelace is easy enough. Have an acknowledge button that calls this custom integration (the file will be recreated when a notification is next made). You may also have to recreate an empty file (using the file notification) so the front end does not complain about a missing file. In this case call a script from the acknowledge button that does both things.