fix(整合): 修复更新日志模态框层级被其他元素遮挡的问题

- 将模态框背景遮罩 z-index 从 z-50 提升到 z-[100]
- 将模态框内容 z-index 从 z-50 提升到 z-[101]
- 确保模态框在所有其他元素（Header 搜索、Sidebar、全屏矩阵等）之上显示

via [HAPI](https://hapi.run)

Co-Authored-By: HAPI <noreply@hapi.run>

src/components/ChangelogModal.tsx

@@ -57,7 +57,7 @@ export function ChangelogModal({ isOpen, onClose }: ChangelogModalProps) {
             animate={{ opacity: 1 }}
             exit={{ opacity: 0 }}
             onClick={onClose}
-            className="fixed inset-0 bg-black/50 z-50"
+            className="fixed inset-0 bg-black/50 z-[100]"
           />
 
           {/* 模态框 */}
@@ -65,7 +65,7 @@ export function ChangelogModal({ isOpen, onClose }: ChangelogModalProps) {
             initial={{ opacity: 0, scale: 0.95, y: 20 }}
             animate={{ opacity: 1, scale: 1, y: 0 }}
             exit={{ opacity: 0, scale: 0.95, y: 20 }}
-            className="fixed inset-4 md:inset-8 lg:inset-16 z-50 flex items-center justify-center"
+            className="fixed inset-4 md:inset-8 lg:inset-16 z-[101] flex items-center justify-center"
           >
             <div className="bg-white dark:bg-gray-800 rounded-2xl shadow-2xl w-full h-full flex flex-col overflow-hidden">
               {/* 头部 */}