fix: exclude fancybox links from pjax and refactor series logic

- Add :not([data-fancybox]) to pjaxExclude to prevent fancybox links from being loaded via pjax
- Refactor series grouping to use a shared hexo._seriesGroups object built once
- Improve performance by avoiding repeated post iteration in both tag and helper
- Version bump to 5.6.1

scripts/helpers/series.js

@@ -1,22 +1,24 @@
-'use strict'
-
-hexo.extend.helper.register('groupPosts', function () {
-  const getGroupArray = array => {
-    return array.reduce((groups, item) => {
-      const key = item.series
-      if (key) {
-        groups[key] = groups[key] || []
-        groups[key].push(item)
-      }
-      return groups
-    }, {})
-  }
-
-  const sortPosts = posts => {
-    const { orderBy = 'date', order = 1 } = this.theme.aside.card_post_series
-    if (orderBy === 'title') return posts.sort('title', order)
-    return posts.sort('date', order)
-  }
-
-  return getGroupArray(sortPosts(this.site.posts))
-})
+'use strict'
+
+// Read pre-built groups from tag/series.js (hexo._seriesGroups)
+// and sort each group according to the sidebar card config.
+hexo.extend.helper.register('groupPosts', function () {
+  const groups = hexo._seriesGroups || {}
+  const { orderBy = 'date', order = 1 } = this.theme.aside.card_post_series
+
+  const result = {}
+  Object.keys(groups).forEach(key => {
+    const arr = groups[key].slice() // copy to avoid mutating the shared data
+    if (orderBy === 'title') {
+      arr.sort((a, b) => {
+        const cmp = a.title.toUpperCase().localeCompare(b.title.toUpperCase())
+        return order === 1 ? cmp : -cmp
+      })
+    } else {
+      arr.sort((a, b) => order === 1 ? a.date - b.date : b.date - a.date)
+    }
+    result[key] = arr
+  })
+
+  return result
+})