oficina / meet Public

Adds team defaults and per-meeting controls for sign-in and waiting rooms. New meetings permit named guests and disable the waiting room; existing meetings retain their original restrictions. Guests retain guest permissions, and disabling a waiting room admits queued guests within the existing capacity limit.

Invitation and holding pages offer browser or native joining. Mac and iOS register the oficina-meet URL scheme, and native authorization supports guest sessions.

Validation: make ci and make race pass with Go 1.26.5; the full browser suite, Mac build, iOS simulator build, and native link tests also pass. This branch is based directly on main and excludes the separate Calls rename.