You have to create a folder of type "Panorama" to upload Skyline documents. Skyline will only show you "Panorama" type folders in the "Upload Document" dialog. I don't see any "Panorama" type folders in your project on PanoramaWeb.
See this page for information on creating folders: https://panoramaweb.org/doc_create_folder.url
You can also change the type of an existing folder:
- From the admin menu (gear icon in the top right corner) select Folder > Mangement
- Select the "Folder Type" tab
- Select "Panorama" from the options under "Folder Type" and click the "Update Folder" button
After this you will be able to choose from the options available ("Experimental data", "QC" etc.) for a "Panorama" folder. You can get more details in the documentation page linked above.
You can learn more about managing folder permissions here: https://panoramaweb.org/add-user.url
I hope this helps.