publish a note in a read-only way (links can be clicked, maybe comments+highlights are hidden)
this may require an additional url (the primary one is for collaborating, the other one for sharing)
or: we make an explicit invitation process. enter email to invite collaborator. only those invited email addresses have access. would make the system more secure, and then we could use the primary url for sharing the current read-only-note. however this makes the primary use-case (write together) possibly a bit harder.
We are good here for now. Notes can be shared by just using the url, if you don't have an account you will see a read only version. You can click edit to request a secure link for editing.
We should think about sharing of notes...