<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Added default sorting and grouping by "Last Updated" for document views.
- Introduced clearer group headers for documents grouped by creation or update date, displaying relative dates or appropriate fallback text.
- **Improvements**
- Enhanced date grouping headers with capitalized, user-friendly text and improved handling of missing dates.
- Added a new localization for "Never updated" to improve clarity in document groupings.
- Initialized document update timestamps at creation to improve date accuracy.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
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