Add ja_jp translation

[virusbb001]

I created Japanese (ja_JP) translations, but I am not good at lean nor mathematics so I need supervising translators.

Once the remaining tasks are complete, I will switch to "Ready".

TODOs:

• Add ja_JP translation to lean4game (I will create pull request later)
• Ask someone to supervise the translation
• Should I squash all commits?

[joneugster]

Thanks for doing this! Commit squashing is optional, will be squashed & merged anyways.

Unfortunately, I don't speak any japanese, so you will need to find help/supervision yourself.

You could ask on Zulip. I suggest looking for topics in the "geographic locality" channels which are about japan or japanese cities. If there are any, that might be a good pool of people.

Let me know when the work is complete in your opinion.

Even better if you find somebody else from the Lean community who could give a superficial review along the lines like "these translations seem to be of high quality and do not contain anything unexpected". (we had some discussion on the chinese translation that it sounded too mechanical at first). But honestly, that's something an LLM can help me verify easily :)