feat: 添加贡献内容更新服务，优化侧边栏贡献模式按钮及相关提示功能

tests/sidepanel-contribution-button.test.js

@@ -5,10 +5,18 @@ const fs = require('node:fs');
 test('sidepanel html keeps a single contribution mode button in header', () => {
   const html = fs.readFileSync('sidepanel/sidepanel.html', 'utf8');
   const matches = html.match(/id="btn-contribution-mode"/g) || [];
+  const serviceIndex = html.indexOf('<script src="contribution-content-update-service.js"></script>');
+  const sidepanelIndex = html.indexOf('<script src="sidepanel.js"></script>');
 
   assert.equal(matches.length, 1);
   assert.match(html, /id="btn-contribution-mode"[^>]*title="进入贡献模式并打开上传页"/);
   assert.match(html, />贡献\/使用<\/button>/);
+  assert.match(html, /id="contribution-update-hint"/);
+  assert.match(html, /id="contribution-update-hint-text"/);
+  assert.match(html, /id="btn-dismiss-contribution-update-hint"/);
+  assert.notEqual(serviceIndex, -1);
+  assert.notEqual(sidepanelIndex, -1);
+  assert.ok(serviceIndex < sidepanelIndex);
 });
 
 test('sidepanel source no longer keeps the legacy upload-page handler on the header contribution button', () => {