Officially use a single translation tool for managing translation / localization (Crowdin / Weblate)
Translating strings and starting a new language is cumbersome, because you need to translate all tokens alone at once, to have it properly submitted.
Crowdin is a great platform, which I have a lot of experience with as a translator. They provide their services for free for open-source projects: https://crowdin.com/page/open-source-project-setup-request.
There has also been some discussion in using weblate: https://weblate.org/en/
The other lemmy projects are using weblate as well, it would make sense to make it the same. I like that weblate is libre as well
https://weblate.join-lemmy.org is the main project translation platform, should not be an issue for the official lemmy app be hosted there too. IMO.
thank you for opening this issue, I'm translator for lemmy and (now defuct) lemmur
For rn at least, just do PRs to the strings.xml like the other ones.