fix: 修复导航栏点击后 active 状态被滚动覆盖的问题

- 添加 isScrollingRef 标记，在点击导航后阻止滚动监听器更新 activeSection
- 改进 section 检测逻辑，使用 sectionTop 和 sectionBottom 精确判断
- 点击导航后 1 秒内不响应滚动检测，确保平滑滚动完成

src/components/layout/header.tsx

@@ -1,6 +1,6 @@
 'use client';
 
-import { useState, useEffect, useCallback } from 'react';
+import { useState, useEffect, useCallback, useRef } from 'react';
 import { Menu, X } from 'lucide-react';
 import { motion, AnimatePresence } from 'framer-motion';
 import { Button } from '@/components/ui/button';
@@ -10,6 +10,8 @@ export function Header() {
   const [isOpen, setIsOpen] = useState(false);
   const [activeSection, setActiveSection] = useState('home');
   const [isScrolled, setIsScrolled] = useState(false);
+  const isScrollingRef = useRef(false);
+  const scrollTimeoutRef = useRef<NodeJS.Timeout | null>(null);
 
   const handleNavClick = useCallback((e: React.MouseEvent<HTMLAnchorElement>, href: string) => {
     e.preventDefault();
@@ -17,6 +19,12 @@ export function Header() {
     const element = document.getElementById(targetId);
     
     if (element) {
+      isScrollingRef.current = true;
+      
+      if (scrollTimeoutRef.current) {
+        clearTimeout(scrollTimeoutRef.current);
+      }
+      
       const headerOffset = 64;
       const elementPosition = element.getBoundingClientRect().top;
       const offsetPosition = elementPosition + window.pageYOffset - headerOffset;
@@ -28,6 +36,10 @@ export function Header() {
       
       setActiveSection(targetId);
       setIsOpen(false);
+      
+      scrollTimeoutRef.current = setTimeout(() => {
+        isScrollingRef.current = false;
+      }, 1000);
     }
   }, []);
 
@@ -35,6 +47,10 @@ export function Header() {
     const handleScroll = () => {
       setIsScrolled(window.scrollY > 20);
 
+      if (isScrollingRef.current) {
+        return;
+      }
+
       const sections = NAVIGATION.map(item => item.href.replace('#', ''));
       const scrollPosition = window.scrollY + 100;
 
@@ -42,7 +58,8 @@ export function Header() {
         const section = document.getElementById(sections[i]);
         if (section) {
           const sectionTop = section.offsetTop;
-          if (scrollPosition >= sectionTop) {
+          const sectionBottom = sectionTop + section.offsetHeight;
+          if (scrollPosition >= sectionTop && scrollPosition < sectionBottom) {
             setActiveSection(sections[i]);
             break;
           }
@@ -53,7 +70,12 @@ export function Header() {
     window.addEventListener('scroll', handleScroll, { passive: true });
     handleScroll();
 
-    return () => window.removeEventListener('scroll', handleScroll);
+    return () => {
+      window.removeEventListener('scroll', handleScroll);
+      if (scrollTimeoutRef.current) {
+        clearTimeout(scrollTimeoutRef.current);
+      }
+    };
   }, []);
 
   return (
@@ -113,7 +135,7 @@ export function Header() {
               <Button 
                 variant="ghost"
                 size="sm"
-                onClick={(e) => {
+                onClick={() => {
                   const element = document.getElementById('contact');
                   if (element) {
                     element.scrollIntoView({ behavior: 'smooth' });
@@ -124,7 +146,7 @@ export function Header() {
               </Button>
               <Button 
                 size="sm"
-                onClick={(e) => {
+                onClick={() => {
                   const element = document.getElementById('about');
                   if (element) {
                     element.scrollIntoView({ behavior: 'smooth' });