feat: 文章顶部自动显示元数据栏（创建日期、更新日期、字数、阅读时间）

- 安装 mkdocs-git-revision-date-localized-plugin，自动提取 git 提交日期
- 覆盖 content.html，在标题下方注入元数据栏
- JavaScript 自动统计中英文字数并估算阅读时间（400 字/分钟）
- 适配 Material SPA 导航 (document$.subscribe)，页面切换时自动更新
- 深色模式兼容

docs/overrides/partials/content.html

@@ -0,0 +1,91 @@
+{#-
+  Override Material theme content partial
+  Adds page metadata bar: creation date, update date, word count, reading time
+-#}
+{% include "partials/tags.html" %}
+{% include "partials/actions.html" %}
+{% if "<h1" not in page.content %}
+  <h1>{{ page.title | d(config.site_name, true)}}</h1>
+{% endif %}
+
+{#- Metadata bar #}
+{% if page.meta and (page.meta.git_revision_date_localized or page.meta.git_creation_date_localized) %}
+<div class="md-page-metadata">
+  <span class="md-page-metadata__item">
+    <span class="twemoji">{% include ".icons/material/calendar-plus.svg" %}</span>
+    创建：{{ page.meta.git_creation_date_localized }}
+  </span>
+  <span class="md-page-metadata__item">
+    <span class="twemoji">{% include ".icons/material/calendar-edit.svg" %}</span>
+    更新：{{ page.meta.git_revision_date_localized }}
+  </span>
+  <span class="md-page-metadata__item" id="word-count">
+    <span class="twemoji">{% include ".icons/material/text-short.svg" %}</span>
+    字数：<span id="word-count-value">...</span>
+  </span>
+  <span class="md-page-metadata__item" id="reading-time">
+    <span class="twemoji">{% include ".icons/material/clock-outline.svg" %}</span>
+    阅读：<span id="reading-time-value">...</span>
+  </span>
+</div>
+{% endif %}
+
+{{ page.content }}
+{% include "partials/source-file.html" %}
+{% include "partials/feedback.html" %}
+{% include "partials/comments.html" %}
+
+{#- Word count & reading time script (SPA-aware) #}
+<script>
+function updateMeta() {
+  var article = document.querySelector('.md-content__inner') || document.querySelector('.md-content');
+  if (!article) return;
+  var text = article.textContent || '';
+  // Chinese characters
+  var chineseChars = (text.match(/[一-鿿㐀-䶿]/g) || []).length;
+  // English/other words
+  var englishWords = text.replace(/[一-鿿㐀-䶿]/g, ' ')
+    .split(/\s+/)
+    .filter(function(w) { return w.length > 0; }).length;
+  var totalWords = chineseChars + englishWords;
+  var minutes = Math.max(1, Math.round(totalWords / 400));
+  var wordEl = document.getElementById('word-count-value');
+  var timeEl = document.getElementById('reading-time-value');
+  if (wordEl) wordEl.textContent = totalWords.toLocaleString();
+  if (timeEl) timeEl.textContent = minutes + ' 分钟';
+}
+// SPA-compatible: run on load and on navigation
+if (typeof document$ !== 'undefined') {
+  document$.subscribe(function() { updateMeta(); });
+} else {
+  document.addEventListener('DOMContentLoaded', updateMeta);
+}
+</script>
+
+{#- CSS for metadata bar #}
+<style>
+.md-page-metadata {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.5rem 1.5rem;
+  margin: 0 0 1.5rem 0;
+  padding-bottom: 0.75rem;
+  border-bottom: 1px solid var(--md-default-fg-color--lightest);
+  font-size: 0.7rem;
+  color: var(--md-default-fg-color--light);
+}
+.md-page-metadata__item {
+  display: inline-flex;
+  align-items: center;
+  gap: 0.2rem;
+  white-space: nowrap;
+}
+.md-page-metadata__item .twemoji {
+  width: 0.9rem;
+  height: 0.9rem;
+}
+.md-page-metadata__item .twemoji svg {
+  width: 100%;
+  height: 100%;
+}
+</style>

mkdocs.yml

@@ -52,6 +52,10 @@ markdown_extensions:
 plugins:
   - search:
       lang: zh                # 中文搜索优化
+  - git-revision-date-localized:
+      enable_creation_date: true
+      type: date
+      locale: zh
 
 extra:
   social: