[Security Solution Docs] [AI Assistant] Include documentation about global security AI assistant (#2176)

Author: KDKHD

solutions/_snippets/ai-assistant-visibility.md

@@ -0,0 +1,8 @@
+You can configure AI Assistant visibility settings in **Stack Management → Advanced Settings → AI Assistant visibility**. These settings control where the AI Assistants appear across Kibana. Depending on your environment, the available options may include:
+
+- Only show assistants in their solutions (default)
+- Show the Observability and Search AI Assistant in other apps
+- Show the Security AI Assistant in other apps
+- Hide all assistants
+
+Choose the option that best fits your workflow.

solutions/security/ai/ai-assistant.md

@@ -401,6 +401,15 @@ When you include a particular event as context, such as an alert from the Alerts
 
 The **Knowledge base** tab of the **Security AI settings** page allows you to enable AI Assistant to remember specified information, and use it as context to improve response quality. To learn more, refer to [AI Assistant Knowledge Base](/solutions/security/ai/ai-assistant-knowledge-base.md).
 
+### AI Assistant visibility [ai-assistant-visibility]
+```{applies_to}
+stack: ga 9.1
+serverless: ga
+```
+:::{include} ../../_snippets/ai-assistant-visibility.md
+:::
+If you select the option to show the Security AI Assistant in other apps, the Security AI Assistant becomes **accessible outside of the Security solution**, for example, in Discover. The chat history remains persistent and is available no matter where you access the assistant within Kibana. 
+
 ### Get the most from your queries [rag-for-esql]
 
 Elastic AI Assistant allows you to take full advantage of the {{elastic-sec}} platform to improve your security operations. It can help you write an {{esql}} query for a particular use case, or answer general questions about how to use the platform. Its ability to assist you depends on the specificity and detail of your questions. The more context and detail you provide, the more tailored and useful its responses will be.