My selfish suggestion would be to add support to populate the part numbers for all the components from LCSC's database. JLCPCB wants these numbers in order to assemble a PCB.
(Currently I use a JLCPCB plug-in to do this in KiCAD.)
The KiCad editor's state is accessible from the web app, we'll do some kind of plugin system like Figma's or just implement these functions as an overlay. We'll see, thanks for the tip!