add instructions for copilot about the projects we have in this repo (Azure#51417)

* add instructions for copilot about the projects we have in this repo

* Update .github/copilot-instructions.md

Co-authored-by: Copilot <[email protected]>

* Update .github/copilot-instructions.md

Co-authored-by: Copilot <[email protected]>

* add some typical workflow for azure management generator

* add a section for azure generator

---------

Co-authored-by: Copilot <[email protected]>

Author: ArcturusZhang

.github/copilot-instructions.md

@@ -1,3 +1,23 @@
+# Project Overview
+
+This repo contains Azure SDKs for various Azure services and tools that generate them.
+
+## Folder Structure
+
+- `/eng/packages/http-client-csharp`: Contains the source code of the generator for Azure Data Plane SDKs (aka Azure Generator).
+- `/eng/packages/http-client-csharp-mgmt`: Contains the source code of the generator for Azure Management Plane SDKs (aka Azure Management Generator).
+- `/sdk`: Contains the individual SDKs for Azure services.
+
+### Azure Generator
+
+- Always run `npm install` in the `/eng/packages/http-client-csharp` directory before running the generator.
+- Always run `/eng/packages/http-client-csharp/eng/scripts/Generate.ps1` to regenerate the test projects to validate the result of generator code changes.
+
+### Azure Management Generator
+
+- Always run `npm install` in the `/eng/packages/http-client-csharp-mgmt` directory before running the generator.
+- Always run `/eng/packages/http-client-csharp-mgmt/eng/scripts/Generate.ps1` to regenerate the test projects to validate the result of generator code changes.
+
 ## SDK release
 
 There are two tools to help with SDK releases: