Add CustardUI script as bundled custom plugin

docs/userGuide/plugins/custardui.md

@@ -0,0 +1,71 @@
+### Plugin: CustardUI
+
+<div id="content">
+
+This plugin automatically injects the [CustardUI](https://custardui.js.org/) auto-init script into the page, enhancing generated static sites with more interactivity and personalization. 
+
+<box type="info">
+
+CustardUI provides additional custom elements like `<cv-toggle>`, `<cv-tabgroup>`, placeholders, page highlighting capabilities, and more.
+
+</box>
+
+To enable this plugin, add `custardui` to your site's plugins.
+
+```js {heading="site.json"}
+{
+  ...
+  "plugins": [
+    "custardui"
+  ]
+}
+```
+
+<panel header="Optional: Specifying a Base URL">
+
+By default, the plugin sets the `data-base-url` attribute for CustardUI to `/`. If you are hosting your site in a subdirectory or need to customize this base URL, you can configure it under `pluginsContext`.
+
+```js {heading="site.json"}
+{
+  ...
+  "pluginsContext": {
+    "custardui": {
+      "baseUrl": "/my-base-url"
+    }
+  }
+}
+```
+
+</panel>
+
+<br>
+
+**Adding a CustardUI configuration file**:
+
+After enabling the plugin, create a `custardui.config.json` file in your site's root directory. This tells CustardUI what options and features to expose to your readers.
+
+<box type="tip">
+
+Make sure your `site.json` ignore list does not exclude JSON files, or MarkBind will not copy `custardui.config.json` into the generated site and the plugin will not work.
+
+</box>
+
+Here is a sample configuration with the settings panel enabled:
+
+```json {heading="custardui.config.json"}
+{
+  "config": {
+    "toggles": [
+      { "toggleId": "mac", "label": "macOS", "description": "Show macOS instructions" },
+      { "toggleId": "win", "label": "Windows", "description": "Show Windows instructions" }
+    ]
+  },
+  "settings": {
+    "enabled": true
+  }
+}
+```
+
+With this configuration, readers will see a settings panel they can use to switch between viewing macOS and Windows content. For more information, check out the [CustardUI documentation](https://custardui.js.org/).
+
+</div>

docs/userGuide/usingPlugins.md

@@ -66,6 +66,7 @@ MarkBind has a set of built-in plugins that can be used immediately without inst
 <include src="plugins/web3Form.md" />
 <include src="plugins/dataTable.md" />
 <include src="plugins/mermaid.md" />
+<include src="plugins/custardui.md" />
 
 ## Using External Plugins
 

packages/core/src/plugins/custardui.ts

@@ -0,0 +1,30 @@
+import { PluginContext } from './Plugin.js';
+
+/**
+ * CustardUI Plugin for MarkBind
+ * Injects the CustardUI auto-init script into every page.
+ */
+
+const getScripts = (pluginContext: PluginContext) => {
+  const baseUrl = pluginContext?.baseUrl || '/';
+  return [
+    // Latest Stable Release
+    '<script src="https://cdn.jsdelivr.net/npm/@custardui/custardui@latest" '
+      + `data-base-url="${baseUrl}"></script>`,
+  ];
+};
+
+const tagConfig = {
+  'cv-toggle': { isCustomElement: true },
+  'cv-toggle-control': { isCustomElement: true },
+  'cv-tabgroup': { isCustomElement: true },
+  'cv-tab': { isCustomElement: true },
+  'cv-tab-body': { isCustomElement: true },
+  'cv-tab-header': { isCustomElement: true },
+  'cv-define-placeholder': { isCustomElement: true },
+  'cv-placeholder-input': { isCustomElement: true },
+  'cv-label': { isCustomElement: true },
+  'cv-insertion': { isCustomElement: true },
+};
+
+export { getScripts, tagConfig };