Now, when you open a local worktree, we immediately send an `OpenWorktree` message
to the server, telling it the name of the folder that you've opened, and the names of all the
collaborators (based on a `.zed.toml` file). The server responds with a unique id for the
worktree.
When starting share this local worktree, you now include this previously-assigned id
in the `ShareWorktree` message.
When joining a worktree, there is no longer a need to provide an access token. The access
is controlled by the set of "collaborator logins" that were provided when the worktree
was initially opened by the host.