fix: enable mermaid by default

server/modules/rendering/html-mermaid/definition.yml

@@ -3,6 +3,6 @@ title: Mermaid
 description: Generate flowcharts from Mermaid syntax
 author: requarks.io
 icon: mdi-arrow-decision-outline
-enabledDefault: false
+enabledDefault: true
 dependsOn: htmlCore
 props: {}