Someone who stands up to Partners HealthCare rather than kneels before it? That's unusual in Boston. But Superior Court Judge Janet L. Sanders so far has refused to let the powerful network of Harvard-affiliated hospitals and doctors push her around. Sanders is reviewing what was supposed to be a routine settlement of an antitrust case. But at a recent hearing, she postponed any further action until Nov. 10. Saying she needs more time to weigh the consequences, she expressed serious concerns about the impact of the settlement on the state's overall health care system and the ultimate cost to consumers.