"Add rule" button in watch folders does nothing - `crypto.randomUUID is not a function` in the console

Now that multiple watch folders are supported I want to add my audiobook library as a second watch rule. I can pick the folder in the "Add watch rule" dialog and the "Add rule" button becomes active, but clicking it does nothing beyond the button press animation, and nothing appears in the server logs. Reproduces in Chrome, Brave, Firefox and Safari. The browser console shows:

Uncaught TypeError: crypto.randomUUID is not a function
    at onAdd (page-*.js)

Running the Docker image over plain HTTP on my home network.

Resolution: crypto.randomUUID() is only exposed in a browser secure context - HTTPS, or localhost. The watch-rule dialog in v2 accidentally depended on it, so on a plain-HTTP LAN address or bare IP the handler throws before the rule is ever submitted, which is why nothing hits the server logs. Two fixes: reach the server over HTTPS (put it behind a reverse proxy with a certificate, or use localhost), or move to v3 where the dependency was removed - switch your image tag from latest to web-v3.0.0-beta. If you take the v3 route, back up your database files first: v3 is still beta and you cannot downgrade to v2 once you've upgraded.