An automatic package_check will be launch at https://ci-apps-dev.yunohost.org/, when you add a specific comment to your Pull Request: "!testme", "!gogogadgetoci" or "By the power of systemd, I invoke The Great App CI to test this Pull Request!"*
I quit, not enough documentation to understand how to package it properly.
npm run build create a dist folder with files. Not sure it needs a systemd service
Solution
PR Status
Package_check results