By Martin Baccardax Stock futures slide as U.S. Warns of Russian attack on Ukraine; Week Ahead: retail sales, Walmart earnings in focus; oil prices top $95 a barrel on Russia tensions, supply slump; Johnson & Johnson set to defend ‘Texas Two Step’ on cancer liabilities and Coinbase QR code ad leads to web traffic “throttle”. 1. — Stock Futures Slide As U.S. Warns of Russian Attack on UkraineU.S. equity futures slumped lower Monday, while Treasury bond prices jumped and oil re-asserted its recent seven-year highs, as investors heeded warnings from the White House that Russia could be preparing…