[META]: Create a tool to translate `en.po` file into `ja.po` file by LLM

Since this is an ambitious endeavour, I prefer to break the project into smaller tasks and prioritise them by importance.

I would propose that we prioritise these issues over others:
1. #3564267: Establish a strategy for LLM-assisted core string translation with glossary and terminology adherence
2. #3564268: Decide which LLM to use
...because they directly affect the quality of the translation, which is indispensable to the success of this project. Also, once we decide on these factors, we can at least start translating the new strings using an LLM, allowing the community to benefit without waiting for full process automation.