What continuing a process into the platform's launch can fail with: the
launch's own refusals, the screens it opens and the requests its burst sends.
A process it finds signed out dies with ProcessNotSignedInError.
The platform declares the same union for its typed continuation (its app
layer pins the launch's error channel to it), so a caller narrows the answer
with catchTag on every platform.
What continuing a process into the platform's launch can fail with: the launch's own refusals, the screens it opens and the requests its burst sends. A process it finds signed out dies with ProcessNotSignedInError. The platform declares the same union for its typed continuation (its app layer pins the launch's error channel to it), so a caller narrows the answer with
catchTagon every platform.