Dovecot ACL + shared namespace (shared/%%u/), acl_shared_dict in mail-state,
idempotent user-patches.sh grants info@ read-only (lookup read) on every
mailbox of ano@, andriy.oblivantsev@, postmaster@ and pre-subscribes the
shared folders so Roundcube's subscribed folder list shows them. Delivery and
passwords untouched; other accounts see no shared folders.
