Residents of Israel’s south were surprised on a recent Saturday morning when they saw heavy construction machinery operating on an empty site west of Kiryat Gat. Government construction projects are almost never carried out on Shabbat, when such work is prohibited according to Jewish law. Many were irked by the irony of the situation: The construction project in question was laying the groundwork for a future ultra-Orthodox city, tentatively known as Plugot. The work was later attributed to a subcontractor’s mistake and was quickly halted. But the incident put the spotlight on a controversial plan that could reshape housing policies for Israel’s ultra-Orthodox communities for years to come. A number of proposed Haredi cities in the Negev have advanced through government approvals as a measure to alleviate a housing crisis threatening the fast-growing community.…