Refactor UptimeStatus component to improve data fetching and user experience

- Removed UpdateTimer component and integrated countdown functionality directly into UptimeStatusIsland.
- Implemented sessionStorage caching for system status data to enhance performance and user experience.
- Added visual countdown display for the next update, improving user awareness of data refresh timing.
- Updated privacy policy to clarify the use of sessionStorage for caching non-personal data.

src/pages/[lang]/privacy.astro

@@ -148,6 +148,9 @@ function parseAndFormatTime(rawTime) {
         <strong>Our website uses cookies strictly for essential functionality.</strong> These cookies are necessary for the
         proper functioning of our website and do not collect any personal information.
       </p>
+      <p>
+        <strong>SessionStorage:</strong> For performance and user experience, we temporarily cache the latest system status data in your browser's sessionStorage. This data is <strong>not personal</strong>, is never sent to our servers, and is automatically deleted as soon as you close your browser tab or window. No personal or identifying information is ever stored in sessionStorage.
+      </p>
       <p>Details about the cookies we use:</p>
       <ul>
         <li>