Enhance documentation on landing zone concept

Added note about landing zone framework for workloads.

Author: brown9804

0_Azure/3_AzureAI/AIFoundry/demos/3_GenAIApps.md

@@ -9,6 +9,9 @@ Last updated: 2025-07-17
 
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+> [!NOTE]
+> A landing zone is a general `cloud framework that sets up the core structure for all workloads`. Each use case (like an app, data pipeline, or API) then builds on top of this framework, using the `same environments (Dev → Test → UAT → Prod) and CI/CD pipelines to move code safely into production.` It’s general by design, but `applied per use case.`
+
 <details>
 <summary><b>List of References</b> (Click to expand)</summary>