Windows installer and app cleanup could leave llama-server.exe running when ollama.exe was killed directly, so cleanup now includes llama-server.exe and taskkill /T.
* app: add code for macOS and Windows apps under 'app'
* app: add readme
* app: windows and linux only for now
* ci: fix ui CI validation
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Co-authored-by: jmorganca <jmorganca@gmail.com>