Break CLI backwards compatibility as planned for refactor/universal-carrier:
- Drop -carrier flag; add -auth (auth provider name), -engine (engine
name for -auth none), -url and -token (SFU endpoint + access token for
direct/none auth mode).
- session.Config.Carrier → Auth + Engine + URL + Token.
- session.Gen() is now generic: auth.Get(cfg.Auth).(auth.RoomCreator)
replaces the hard-coded switch on carrier names.
- Register a "none" carrier in builtin (registerDirect) that bypasses
auth and connects directly to any engine with caller-supplied URL+Token.
- auth/telemost.Provider.Issue now accepts a raw room-ID hash in addition
to a full https://telemost.yandex.ru/j/<id> URL.
- Plumb Engine/URL/Token from session.Config through server.Run,
client.Run/RunWithReady, bringUpLink, link.Config, transport.Config, and
carrier.Config so the "none" carrier has access to them end-to-end.
- Update all tests and mobile.go call sites.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
