25d80bc31d
Add POST /internal/sessions/email/confirm-link: it verifies a deeplink token via ConfirmByToken and, for a login, mints a session (the deeplink page signs in with it); for a link, attaches the confirmed email and reports "confirmed" or "merge_required" (the app drives the interactive merge). The token, not a request session, is the authorization. Add LinkConfirmation.IsLogin() and integration tests for the login, link and merge branches (the token is read from the mailed link). The gateway RPC, live event and SPA route follow.