CARLSBAD, Calif. — Thousands of California parents who want to see their students return to school have experienced an emotional roller coaster this week, with many saying it’s hard to put any trust in the government’s conflicting narrative and decisions on school reopenings. In early March, Gov. Gavin Newsom announced a $6.6 billion incentive plan, declaring that it was time for kids to safely return to the classroom. But just six days into the push, one of his health department appointees denied the applications of three San Diego-area school districts to expand in-person learning, overturning a decision by the top county public health official who had approved the districts’ opening plans two weeks ago.