TRURO — About 700 people arrived at Truro Central School on Nov. 28 ready for a climax and dénouement to months of dramatically rising tension and civic disagreement here. But even using the school’s library and cafeteria as well as the gymnasium, the building could hold no more than 523 voters. With nearly 200 more stranded outside, no votes on articles could be held, and the meeting had to be postponed for the fourth time.