Supercharge.info lists the opening date as 2015-07-02.
This information is probably based on the information from the TFF-Forum:
July 19, 2025 by user psimeon and others.
The first people seem to have been charging on July 2
The pictures of the construction and opening only show 6 stalls total (2 angled + 4 straight).
The 2 additional straight spaces were added later, I'm not sure when at the moment. They were there in my July 2020 pictures.
I wonder where the power modules for group 4 have been installed, as the wooden "house" didn't seem to include extra space for an additional charger. I'll need to take a closer look on my next visit.