Improved Japanese translation (japanese.json)

[hisui3393]

I have updated the Japanese translation file (japanese.json) to improve usability and consistency.

This is still an incomplete work in progress, but I have started refining some UI terms and improving clarity in areas related to input and usability.

If there are any inconsistencies or suggestions, I would appreciate feedback.
Japanese.json

[niksedk]

Thx, added in commit: 3550b1d