feat(docs): add Indonesian README translation

[salmanabdurrahman]

Summary

• add README_id.md in formal Indonesian following existing condensed translation pattern
• add Bahasa Indonesia to language switcher in all README variants
• align version/module counts to pass docs validation

Testing

• bash scripts/validate-docs.sh

[pszymkowiak]

Thanks for the translation! Looks good. Two things needed before we can merge:

1. Rebase on develop — there's a merge commit that needs to be removed:

   git fetch upstream develop
   git rebase upstream/develop

2. Add DCO sign-off — our CI requires Signed-off-by in commits:

   git commit --amend -s --no-edit
   git push --force-with-lease

[salmanabdurrahman]

Thanks for the feedback! I've rebased the branch on develop, removed the merge commit, and added the required DCO sign-off. The PR should be updated now