docs(portal): add Aspire 9 prereqs and troubleshooting; keep one-command fallback documented

Author: srnichols

management-portal/README.md

@@ -14,6 +14,18 @@ Run locally with one command or via the AppHost. Defaults to in-memory data; set
 - Run AppHost: dotnet run --project management-portal/AppHost
 - Portal URL: http://localhost:8081
 
+Prereqs for Aspire run (CLI)
+- .NET 9 SDK installed (9.0.4xx or newer)
+- .NET Aspire 9 workload and tools installed
+	- dotnet workload install aspire
+	- Ensure Aspire Hosting SDK pack is 9.x under C:\Program Files\dotnet\packs\Aspire.Hosting.Sdk
+	- Install Aspire Distributed Control Plane (DCP) and Aspire Dashboard (via Visual Studio Installer > Individual components > .NET Aspire 9)
+- CLI: aspire --version should show 9.x
+
+Troubleshooting
+- If aspire run says "not an Aspire app host project" or AppHost complains about missing DCP/Dashboard, install the Aspire 9 SDK pack and DCP/Dashboard as above.
+- Use the one-command local scripts as a fallback while you set up Aspire.
+
 ## Config
 - DAB_GRAPHQL_URL: e.g. http://localhost:8082/graphql