chimp 0.51.1 (Selenium 2 / cucumber e2e runner) was the last dependency
pulling native fibers@1.x, which cannot compile on Node 22 and failed the
clean Docker image build (node-gyp: no prebuilt, no python). Not imported
anywhere. Also add python-is-python3 to the builder stage so node-gyp can
find python for any other native dep. Boot + REST smoke green.
