Blake Lively spent seven years “obsessively developing” her new business venture. The 36-year-old star has created a new haircare brand called Blake Brown Beauty, and Blake has taken to social media to discuss the evolution of her business. The actress – who is married to movie star Ryan Reynolds – wrote on Instagram: “Ever since I was a kid, through adolescence, early adulthood, motherhood, work, personal life, whenever, wherever, the single most identifiable part about me has always been my personalit— no? Not my personality? Oh… My hair. “It’s my longest companion in life. For 36 years and …