I'll add a reset button in my next updates, but for now, here's the nuclear option:
Open your dev tools (google "how to open dev tools" because it depends per browser) and navigate to the "Application" tab. Under "storage," you'll find IndexedDB, which should have a "/userfs" section. If you click that, it'll show you a button to delete the database.
Click that. If you refresh, your data should be wiped. (The game autosaves every 30 seconds, so you'll need to refresh before the autosave happens.)
I'm trying to send a screenshot, but it appears that itch is unhappy.
So here: https://imgur.com/a/DFfLmqC