The memo that shook Wall Street didn’t come from a regulator. It came from a job posting. Late last year, OpenAI quietly assembled a team of over 100 former bankers — poached from JPMorgan, Goldman Sachs, and Morgan Stanley — and put them to work at $150 an hour training AI to build the financial models, IPO valuations, and pitchbooks that junior analysts once spent 100-hour weeks perfecting. The initiative, codenamed Project Mercury, wasn’t announced with fanfare. It didn’t need…