✨ Feat: enhance Mermaid configuration and fix initialization bug (#617)

* 🐛 Fix: Mermaid initialization conflict error

* ✨ Feat: enhance Mermaid configuration with security level, look, and font family options

layouts/_partials/plugin/echarts.html

@@ -7,7 +7,7 @@
 {{- $file := .Options.file -}}
 {{- $attrs := printf `style="width: %v; height: %v;"` $width $height -}}
 
-<div class="echarts-container">
+<div class="diagram-container">
 {{- dict "Label" "Copy ECharts code" | partial "plugin/diagram-copy-btn.html" -}}
 <div class="echarts" {{ $attrs | safeHTMLAttr }}></div>
 {{- $content := strings.TrimSpace .Inner -}}

layouts/_partials/plugin/mermaid.html

@@ -1,7 +1,7 @@
 {{- /* Mermaid support for code fences extended and shortcodes. */ -}}
-<div class="mermaid-container">
+<div class="diagram-container">
   {{- dict "Label" "Copy Mermaid code" | partial "plugin/diagram-copy-btn.html" -}}
   <pre class="mermaid">{{ .Inner | safeHTML }}</pre>
-  <template>{{ .Inner | safeHTML }}</template>
+  <template><pre class="mermaid">{{ .Inner | safeHTML }}</pre></template>
 </div>
 {{- /* EOF */ -}}