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/mermaid.pug

@@ -282,12 +282,14 @@ script.
       const theme = document.documentElement.getAttribute('data-theme') === 'dark' ? '!{theme.mermaid.theme.dark}' : '!{theme.mermaid.theme.light}'
       ele.forEach((item, index) => {
         const mermaidSrc = item.firstElementChild
-        // Clean up event listeners before removing old SVG
+        // Clean up event listeners and stale content before re-rendering
         if (item.__mermaidAbortController) {
           item.__mermaidAbortController.abort()
         }
         const oldSvg = item.querySelector('svg')
         if (oldSvg) oldSvg.remove()
+        const oldError = item.querySelector('.mermaid-error')
+        if (oldError) oldError.remove()
         let config = {}
         try {
           config = mermaidSrc.dataset.config ? JSON.parse(mermaidSrc.dataset.config) : {}