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/script.js

@@ -665,7 +665,7 @@ document.addEventListener('DOMContentLoaded', () => {
 
             // 使用更高效的搜索算法
             const matchedItems = searchIndex.items.filter(item => {
-                return item.searchText.includes(searchTerm);
+                return item.searchText.includes(searchTerm) || PinyinMatch.match(item.searchText, searchTerm);;
             });
 
             // 按页面分组结果
@@ -800,6 +800,12 @@ document.addEventListener('DOMContentLoaded', () => {
                     title.removeChild(title.firstChild);
                 }
                 title.appendChild(titleFragment);
+            } else if (PinyinMatch.match(title.textContent, searchTerm)) {
+                const arr = PinyinMatch.match(title.textContent, searchTerm);
+                const [start, end] = arr;
+                title.innerHTML = title.textContent.slice(0, start) +
+                    `<span class="highlight">${title.textContent.slice(start, end + 1)}</span>` +
+                    title.textContent.slice(end + 1);
             }
 
             // 安全地高亮描述中的匹配文本
@@ -846,6 +852,12 @@ document.addEventListener('DOMContentLoaded', () => {
                     description.removeChild(description.firstChild);
                 }
                 description.appendChild(descFragment);
+            } else if (PinyinMatch.match(description.textContent, searchTerm)) {
+                const arr = PinyinMatch.match(description.textContent, searchTerm);
+                const [start, end] = arr;
+                description.innerHTML = description.textContent.slice(0, start) +
+                    `<span class="highlight">${description.textContent.slice(start, end + 1)}</span>` +
+                    description.textContent.slice(end + 1);
             }
         } catch (error) {
             console.error('Error highlighting search term');