San Francisco Opera has an almost $8 million deficit. But the company doesn’t seem particularly worried. Rather than sit back and play it safe, Pamela Rosenberg, the company’s general director, has ambitious plans. “We are not going to get through this economic downturn and come out the other end by replacing quality with mediocrity,” Ms. Rosenberg, who has set the company on course to becoming America’s most adventurous opera house, said in a recent telephone interview.”