Suplanus/Suplanus.Sepla ? reverse-engineered prompt

Build me a small helper library for the EPLAN API that makes common tasks easier and includes a few working example apps so I can see how to use it in real projects.

I want the solution to include the core Sepla library and some simple demos for things like working offline, showing a preview, exploring navigator and item type examples, exporting SVG, and a parts management example. Keep it practical and focused on helping someone get started fast with EPLAN automation.

Please make the code easy to understand, with a couple of sample projects that I can open and run. If you need to check current EPLAN API details online to make sure the examples are realistic, go ahead and do that.