Implement advanced spreadsheet UI features

[code-by-sia]

Summary

The roadmap includes an unfinished item for advanced UI features.

Goal

Track remaining user-interface improvements needed to make OpenWebSheet competitive with desktop spreadsheet applications.

Candidate features

• Freeze rows and columns.
• Multi-sheet management improvements.
• Context menus.
• Keyboard shortcut coverage.
• Drag-fill/autofill handle.
• Improved selection and navigation UX.
• Accessibility and touch-device improvements.

Acceptance criteria

• Break down this umbrella issue into smaller issues as requirements become clearer.
• Document supported UI interactions.

Source

* [ ] advanced ui features