Before the doom descended last week, OpenAI researchers were euphoric.  The startup claimed its latest internal AI model had solved one of the famously complicated Millennium Prize math problems, an experiment it embarked on after seeing rumors online that archrival Anthropic had already done so. Researchers called each other excitedly and posted about their triumph on Slack.  The breakthrough was seen internally as a victory in a ruthless commercial race to build AI tools smarter than humans, a multitrillion-dollar sprint that promised an unprecedented windfall of wealth and power when the two companies eventually go public—tentatively planned for as soon…