Feedback if spark can not fullfill the request

I played around and spark is pretty silent about things it can not do
E.g. I asked to create a python app (seems not supported) and then i got a working react application which is fine.

However spark could give feedback abou things it can not fullfill

The issue names no file, test, or entry point. Start by clarifying how unsupported requests such as Python app creation should be detected and where Spark should report those limitations. Done means users receive clear feedback instead of silently getting a different application type.

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