Extensions (Legacy) greyed out in Photoshop 25.11

Is CEP extensions not supported in Photoshop now?

I am using Photoshop and Premiere Pro on Windows 11. I downloaded the source code from github, and put it into the folder "C:/Program Files/Common Files/Adobe/CEP/extensions/CEP_HTML_Test_Extension-12.0".

The extension works well in Premiere Pro, but in Photoshop, the "Extensions (Legacy)" is grey and I can't do anything. I have tried all ways I can find but nothing happened.