feat: 更新 lazyload 配置，支持原生 lazyload 功能

feat: 代碼優化
feat: 優化 pageType 邏輯
fix: 修復解密文章後， chartjs 沒有加載的 bug

layout/includes/third-party/math/index.pug

@@ -1,10 +1,10 @@
 case theme.math.use
   when 'mathjax'
-    if (theme.math.per_page && (is_post() || is_page())) || page.mathjax
+    if (theme.math.per_page && (['post','page'].includes(globalPageType))) || page.mathjax
       include ./mathjax.pug
 
   when 'katex'
-    if (theme.math.per_page && (is_post() || is_page())) || page.katex
+    if (theme.math.per_page && (['post','page'].includes(globalPageType))) || page.katex
       include ./katex.pug
 
 if theme.mermaid.enable