nathanmathewv/InformationConvergencePlatform ? reverse-engineered prompt

Build me a Flask web app for an information convergence platform that lets me upload XML schemas, run queries against data from SQL databases, XML files, and spreadsheets, and see the results in one clean, uniform table view.

I want a simple homepage where I can paste or upload a schema, save it, then submit a query in JSON format and run it. The app should handle the query execution, combine results from the different data sources, and show the output nicely in the browser. It should also let me download the results as JSON, CSV, or TXT.

Please keep the UI straightforward and easy to use, with separate pages or sections for uploading schemas, running queries, and viewing results. If you need to, look up current docs online for any Flask or file handling details. Make sure it all works end to end with the existing project structure, and if there are helper modules already in place, wire them up instead of reinventing everything.