Might like to investigate this particular userscript by mempo /t/Userscript-Wanikani-Procrastination-Annihilation/11253/1
It’s only intended to stop you from using the forums instead of doing your reviews, but it’ll do exactly what you want if you can just modify it to:
-> Have it run on all pages
-> Change the trigger from clicking forum link to (whatever really, like clicking anywhere?)