feat: artalk 支持點擊打開大圖

feat: 設置了隨系統而切換淺色和深色模式後，評論和 mermaind 也會跟隨切換顏色
feat: artalk 最新評論，從 artalk 配置讀取頭像 CDN 和默認頭像
fix: 修復代碼塊在未展開時，點擊複製按鈕，無法複製的 bug
improvement: 代碼和性能優化
improvement: artalk 獲取評論數，由 LoadCountWidget 改為 loadCountWidget

layout/includes/head/config.pug

@@ -127,5 +127,6 @@ script.
     percent: {
       toc: !{theme.toc.scroll_percent},
       rightside: !{theme.rightside_scroll_percent},
-    }
+    },
+    autoDarkmode: !{theme.darkmode.enable && theme.darkmode.autoChangeMode === 1}
   }

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

@@ -1,4 +1,4 @@
-if theme.abcjs.enable
+if theme.abcjs && theme.abcjs.enable
   if theme.abcjs.per_page
     if is_post() || is_page()
       include ./abcjs.pug

layout/includes/third-party/card-post-count/artalk.pug

@@ -4,7 +4,7 @@ script.
   (() => {
     const getArtalkCount = () => {
       const runWidget = () => {
-        Artalk.LoadCountWidget({
+        Artalk.loadCountWidget({
           server: '!{server}',
           site: '!{site}',
           countEl: '.artalk-count'