QGIS Union Overlay Analysis

I have two vector layers that need to be merged with a Union overlay in QGIS. Your task is to run the analysis, resolve any topology issues that appear during the process, and deliver a clean layer containing every polygon from both sources with their attribute tables combined.

Please keep the geometry valid, preserve all existing fields, and add any automatically generated ID columns if required by QGIS. I will review the result by loading it alongside my originals, so accuracy is essential; all overlaps must be properly split and attributed.

Deliverables
• The final union layer saved in its native GeoPackage plus a copy exported as Shapefile.
• A brief note (a few lines is fine) describing the steps you followed and any fixes you applied.

I will send the source layers as soon as we start. Let me know if you foresee any issues or need further details before running the Union.