feat: add wordcount helpers, waline lightbox, and extensive bug fixes

- wordcount/min2read/totalcount built-in helpers (replaces hexo-wordcount)
- cloudTags random sort support
- waline lightbox via MutationObserver
- subtitle: seq guard prevents stale API response race
- newest-comments: escapeHtml XSS fix, unified fetchAndRender with cache fallback
- katex: try/catch asset load, encrypt re-render
- chartjs: destroy charts on pjax, fix theme property check
- mathjax: DOMContentLoaded instead of load
- mermaid: clean stale error elements
- medium-zoom: single instance, detach on pjax
- getScrollPercent: WeakMap cache with resize invalidation
- overflowPaddingR: avoid stale DOM refs
- readmode: dedupe button, pjax cleanup
- hexo-blog-decrypt: null-guard translateFn and encryptFn
- tw_cn: expand skipped translate tags
- localStorage: try/catch setItem
- cdn.js: fix [lib|dist]* character class regex bug
- findArchivesTitle: support custom archive_dir
- shuoshuoFN: guard moment.tz when timezone empty
- umami: no-store cache, error handling, path param
- artalk: vote config option
- bump version 5.7.1.260810

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

@@ -77,5 +77,7 @@ script.
     }
 
     btf.addGlobalFn('encrypt', loadMathjax, 'mathjax')
-    window.pjax ? loadMathjax() : window.addEventListener('load', loadMathjax)
+    if (window.pjax) loadMathjax()
+    else if (document.readyState === 'loading') document.addEventListener('DOMContentLoaded', loadMathjax)
+    else loadMathjax()
   })()