Translations: Improve Simplified Chinese localization —— BG2GSG

[mc-doge666]

Summary

This PR improves the Simplified Chinese localization by adding
missing translations and updating existing translations for
consistency.

I have reviewed, corrected, and completed the vast majority of
the Simplified Chinese translations in the project. However,
approximately 55 entries are still marked as unfinished. Most
of these were intentionally left untranslated because I believe
they either do not require translation, or I was uncertain about
the correct wording, formatting, or how they should be presented
within the translation files.

Request for Review

I was unable to perform a full build and translation validation
because of dependency issues in my local environment.

The changes were made directly in the .ts files, so I would
appreciate it if the maintainers could verify that no TS/XML
syntax errors were introduced and that the translation files
compile successfully.

I would also appreciate any feedback regarding the remaining
unfinished entries, particularly those that may require
translation or special formatting.

_{_Additionally, my original intention was to contribute some code changes and new functionality to the project. However, I ran into difficulties setting up the development environment due to dependency installation and configuration issues. I found that some parts of the contribution and development documentation were not detailed enough for my setup. If possible, I would encourage the maintainers to further improve the development and contribution guides, as this could help new contributors get started more easily and enable more code contributions in the future._}

Please let me know if any corrections are needed.