* Add ability to sync all LINE contacts, which is relevant because the
list of recent chats excludes users you haven't spoken to lately.
* Add bot command to list all contacts.
* Allow inviting a puppet to a DM to create a portal for that LINE user,
instead of having to wait for that user to message you first.
...that are sent from another client.
Also look up the profile data for the user's LINE account on sync,
including at startup, so that there's always a puppet available.
