The stdio JSON-RPC transport deliberately re-raises host I/O errors
(ENOSPC, a locale that cannot encode the server's copy). _announce now
catches (OSError, ValueError) and returns False so present() falls back
to the terminal instead of losing the link and failing the run.
Also pins the ui-tui event -> presenter routing with a dispatch-level
test, and names the billing presenter factory like its sibling
(createBillingVerificationPresenter).
4ca6f9e91c