Is your feature request related to a problem? Please describe.
Currently you can either allow/restrict people uploading avatars via toggling their ability to create accounts, but there isn't any way to limit what size of avatars can be uploaded (e.g. Max 512 KiB). Without a way of limiting the size, people can upload avatars that impair the performance for themselves and others.

Describe the solution you'd like
Add a field to the admin section of Hubs instances to specify the maximum file size of uploaded avatars.

Describe alternatives you've considered
An alternative could be to prevent users from creating accounts (and therefore uploading avatars) and forcing them to use a predefined set of avatars that are known to be performant, but this disallows custom avatars and prevents users from performing actions that require them to be signed in.

Additional context
A similar setting to control the size of uploaded/published scenes in Spoke could also make sense and remove the need for it to be hard coded at 128 MiB.

This feature was requested by a user at the 2025-02-18 Hubs Dev Meetup.