“This happened on Dec.r 30, 2003. That may seem a while ago but it won’t when it happens to you. And it will happen to you. The details will be different, but it will happen to you. That’s what I’m here to tell you.” In the first lines of The Year of Magical Thinking — currently staged by Long Wharf Theatre at various locations in and near New Haven through Dec. 10 — the lone actor on stage establishes herself. She’s a reporter, drawing power from facts. Her voice matches the unblinking eye and mind implicit in her words. But that voice, with its mix of sharpness and vulnerability, also flags what’s ahead: that the coming waves of shock and grief will tip over some facts, wash away some logic. If facts and logic have been your guiding lights, how do you navigate the next days, months, years, without them? And where are you at the end of it?