With an unemployment rate of 2.6 percent, a diverse economy anchored by health and education institutions, and a flourishing tech and life sciences sector, Greater Boston appears poised for continued growth, even with the specter of a potential recession on the horizon. But, like many other growing U.S. cities, the demand for housing far outstrips the supply. Much of the expanding workforce is in danger of being priced out of the market, as are many longtime residents.