A turn that ends on an API error now goes through the normal stop handling

When a turn ends, Claude Code checks whether it should run its stop handling, the steps it takes once the model has stopped. It now also runs that handling when the last message is an API error, meaning an error that came back from Anthropic's service instead of a normal reply. Before, an API error at the end of a turn did not count on its own.

Claude Code also now records that the model stopped, noting that this did not happen through the keepalive path, which is the mechanism that keeps a session going between turns.