The chat no longer hangs when the model doesn't answer

A turn whose model doesn’t answer no longer waits for minutes: it stops at 120 s, instead of failing later with a service error. The chat shows the translated notice with Retry and the reason stays in the turn log; it isn’t retried on its own.

A reply that stops sending content is cut too: at 120 s if nothing arrived yet, or after 45 s of silence past the last content.