feat(search): 引入拼音搜索

* add pinyin search

* style(highlight): keep theme-aware background

- restore theme-aware .highlight with --highlight-bg

- add highlight vars for light/dark

chore: load pinyin lib before script.js

- ensure pinyin-match.js loads before script.js to avoid runtime dependency issues

docs: add third-party notice for pinyin-match

- add placeholder notice; replace with upstream license after verification

---------

Co-authored-by: neo <neo@example.com>
Co-authored-by: Maintainer (PR Edit) <maintainer@local>

src/generator.js

@@ -877,6 +877,12 @@ function copyStaticFiles(config) {
         console.error('Error copying style.css:', e);
     }
 
+    try {
+      fs.copyFileSync('assets/pinyin-match.js', 'dist/pinyin-match.js');
+    } catch (e) {
+      console.error('Error copying pinyin-match.js:', e);
+    }
+  
     // 复制JavaScript文件
     try {
         fs.copyFileSync('src/script.js', 'dist/script.js');