STL to STEP Assistant

- Improved the layout of the Recent Files list - Improved the quality and stability of automatic BRep conversion, with better results for common planes, cylinders, cones, spheres, and fillets in mechanical models - Improved BRep previews with clear, high-contrast colors for converted regions and regions retained as triangles, making conversion results easier to inspect - Improved the STEP export workflow by reusing preview results for faster exports, and fixed extra surfaces appearing in some exported models

- Added Faceted STEP preview: review Original, High, Balanced, and Small Size quality modes before export, with source file details and an in-scene preview of the converted model; you can also hide the original model to inspect the result alone - Improved conversion preview access: Faceted and BRep conversion previews remain free to use, and the daily free BRep export quota has been removed - Improved BRep surface reconstruction: better recognition of chamfers, fillets, cylinders, cones, frustums, and regular transition bands, reducing unnecessary faceted fallback areas in mechanical models - Improved BRep preview and export consistency: preview results can be reused during export, reopening preview no longer recomputes unnecessarily, and several preview display and region toggle issues have been fixed

- Added BRep conversion preview: review analytic regions, coverage, fallback regions, and region details before export, with a visual preview of the conversion result in the scene - Improved Mesh-to-BRep results: enhanced recognition for planes, cylinders, cones, and spheres, making converted mechanical parts more structured and easier to edit - Improved scene controls: added a floor show/hide button and kept the scene still by default for more stable viewing and interaction - Improved recent file management: recent files now support per-item deletion and clear all, including cleanup of matching imported files stored by the app