The four-year state-approved affordable housing moratorium in Ridgefield is set to expire next year.  The Assistant Town Planner has drafted language for a proposed regulation in an attempt to guide developers to business zones while protecting residential neighborhoods.  The projects would require first floor commercial use.  The state's aim is to have 10 percent of housing in each town qualify as affordable, but most towns do not meet the goal.  If 30-percent of a development is considered affordable, they can bypass local zoning rules on density and other standards.  A public hearing on the proposed ordinance in Ridgefield will be held tonight.