nav新增动画，修复潜在的性能和bug，优化动画流畅度

components/ShatterTransition.tsx

@@ -7,9 +7,9 @@ interface ShatterTransitionProps {
   onComplete: () => void;
 }
 
-// 增加网格密度以获得更细腻的破碎感
-const GRID_COLS = 10;
-const GRID_ROWS = 10;
+// 优化性能：减少碎片数量
+const GRID_COLS = 7;
+const GRID_ROWS = 7;
 
 export default function ShatterTransition({ isActive, onComplete }: ShatterTransitionProps) {
   const [isAnimating, setIsAnimating] = useState(false);