Squarespace Inc. SQSP stock rallied in the extended session Thursday after the company said it was buying millions of accounts from Google’s Domain business for an undisclosed price. Squarespace shares rallied as much as 6%, following a 2.4% rise to close the regular session at $31.39. Under the deal, the online brand-building platform will acquire about 10 million domains from Google, and said it will honor renewal prices for all existing Google Domains customers “for at least 12 months following the closing of the transaction,” and provide other incentives for customers. Squarespace said it expects the deal to close…