[HarshCasper]

The repo had no CI and no test, and make run failed with "Couldn't find a project to run".

• make run now runs dotnet run --project ChaosEngDemo.
• New test.sh:
  • injects a fault on DynamoDB PutItem through the Chaos API (400 AccessDeniedException, probability 1)
  • checks the demo prints "AWS SDK Exception caught!" and the error code, and did not insert the item
  • removes the fault, reruns the demo, and checks the item is stored in Products and read back
  • removes only its own fault on exit
• The fault uses a 400 because with a 503 the .NET SDK retries with backoff for about 5 minutes.
• New make test target, and the README links the Chaos API docs.
• New workflow sets up .NET 9, builds, and runs make test.

Tested locally against LocalStack, with the demo run in a mcr.microsoft.com/dotnet/sdk:9.0 container.

https://claude.ai/code/session_01DZfDmzUBPqNAu3yFKyfCNM