Feat: add Chinese (zh) locale

[Anyexyz]

Description 📣

This PR adds Simplified Chinese translations for the Infisical web interface and configuration files.
It enhances accessibility for Chinese-speaking users and improves the global usability of the project.

No breaking changes were introduced, and existing language files remain unaffected.

Type ✨

• [ ] Bug fix
• [x] New feature
• [ ] Improvement
• [ ] Breaking change
• [ ] Documentation

Tests 🛠️

The following tests were performed to verify the translations:

# Run development server
npm run dev

# Steps:
# 1. Switch the application language to "中文 (Simplified Chinese)".
# 2. Verify that all UI components (dashboard, settings, billing, audit logs, etc.) display correct translations.
# 3. Ensure no broken keys or missing placeholders appear in the console.

[maidul98]

:white_check_mark: Snyk checks have passed. No issues have been found so far.

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