Translate default version property documentation

[mintlify]

Summary

• Added translated "Default version" section to navigation.mdx for Spanish, French, and Chinese
• Added translated default field documentation to settings.mdx versions section for all three languages

These translations correspond to the changes from PR #4311 which documented the default property for version navigation.

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Note

Low Risk
Low risk: documentation-only changes across localized MDX files with no runtime or configuration logic modifications.

Overview
Adds a translated “Default version” section to navigation.mdx in es, fr, and zh, explaining that the first versions entry is default unless a version sets default: true, with an accompanying JSON example.

Updates settings.mdx in the same locales to document the versions[].default boolean field (and fixes minor punctuation/quoting in the Chinese tag description).

^{Written by Cursor Bugbot for commit fe7f508. This will update automatically on new commits. Configure here.}