Update Indonesian locales/ files

[mrubens]

Follow up to #4672

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Important

Add Indonesian CODE_OF_CONDUCT.md and update language links in various locale files.

• Locales:
  • Add CODE_OF_CONDUCT.md in Indonesian (locales/id).
  • Update language links in README.md for de, hi, and ja locales to include Indonesian.
  • Update language links in CODE_OF_CONDUCT.md for pl locale to include Indonesian.

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