Her father and others involved in the conservatorship maintained that it was a smooth-running machine that had rescued her from a low point and benefited Ms. Spears, and that she could move to end it whenever she wanted. All the while, she stayed largely silent on the subject in public. But now, confidential court records obtained by The New York Times reveal that Ms. Spears, 39, expressed serious opposition to the conservatorship earlier and more often than had previously been k