feat: initial release of pengzhan.dev personal editorial blog platform

- Editorial web platform built with Node.js, Express, EJS, and Vanilla CSS
- Markdown content engine with YAML frontmatter, bilingual variants, and hot-reload watcher
- Unified SQLite with FTS5 search indexing, query logging, and schema filters
- Centered editorial post layout with margin-docked left TOC and mobile bottom sheet
- WordPress-grade comment system with moderation dashboard and bulk operations under /guanli
- Complete SEO suite (JSON-LD structured data, RSS/Atom feeds, XML sitemap, robots.txt)
- CI/CD workflows for linting, security audits (Gitleaks), automated tests, and Docker releases

sample-content/plugins/google-analytics/index.js

@@ -0,0 +1,17 @@
+module.exports = {
+  injectHead({ pluginConfig }) {
+    const trackingId = pluginConfig.tracking_id;
+    if (!trackingId) return '';
+
+    return `
+    <!-- Google Analytics (GA4 via Plugin) -->
+    <script async src="https://www.googletagmanager.com/gtag/js?id=${trackingId}"></script>
+    <script>
+      window.dataLayer = window.dataLayer || [];
+      function gtag(){dataLayer.push(arguments);}
+      gtag('js', new Date());
+      gtag('config', '${trackingId}');
+    </script>
+    `;
+  }
+};