SAN DIEGO — San Diego may soon merge city efforts focused on enforcement of wage laws, worker safety rules, sick-day requirements and guidelines for selecting city contractors. The goal would be streamlining those efforts, now handled by several different city agencies, and combining them under a new Office of Labor Standards Enforcement. Five of the City Council’s nine members endorsed creating the new agency in budget request memos submitted this month. Those memos will help determine the proposed budget Mayor Todd Gloria is scheduled to unveil in April. Programs that would fall under the Office of Labor Standards Enforcement would likely include minimum wage, living wage, prevailing wage, earned sick days, labor compliance and equal opportunity contracting.