[Improvement]: Simplified Chinese translations are out of sync with en.json

What needs improvement?

The Admin dashboard's Simplified Chinese locale (packages/admin/dashboard/src/i18n/translations/zhCN.json) has fallen behind the current English translation source (en.json).

This causes two kinds of issues in the Simplified Chinese Admin UI:

• Newer Admin features can fall back to English because the corresponding zhCN keys are missing.
• Some translation keys have changed upstream (for example Admin search group names moved from camelCase to graph-entity snake_case names), leaving stale keys in zhCN.json that are no longer used.

There are also a small number of clear translation-quality issues in the existing file, such as untranslated Yes/No values, awkward API-key wording, and inconsistent punctuation.

Expected behavior

zhCN.json should track the current en.json structure so Simplified Chinese users do not see avoidable English fallbacks in the Admin dashboard.

The locale should have:

• the same key structure as en.json;
• no stale/extra keys;
• matching value types;
• preserved interpolation placeholders and React Trans tags;
• natural Simplified Chinese wording for the added strings.

Proposed scope

Update only packages/admin/dashboard/src/i18n/translations/zhCN.json to:

• backfill missing translations;
• update renamed/refactored keys so the existing locale follows the current English source structure;
• translate newer Admin areas such as search index management, roles/policies, translation management, product options, refund reasons, MFA, and related additions;
• fix clear existing mistranslations and punctuation inconsistencies;
• validate the finished locale recursively against the current en.json.

A PR implementing this scope is already open as #16831.

Because this is a large translation backfill (>500 changed lines), the repository's contribution review requires the linked issue to carry the help-wanted label. If this scope is appropriate, please add help-wanted so the contribution can proceed through review.