feat: mouse support

[mpryor]

Summary

Add mouse interaction support for users who prefer point-and-click alongside keyboard navigation.

Details

• Click to select a cell / move cursor
• Scroll wheel for vertical navigation
• Click column headers to sort
• Drag column borders to resize columns
• Right-click context menu for common actions (filter, copy, sort, hide column)
• Double-click to expand/view full cell content

Use Cases

• Lower barrier to entry for users unfamiliar with vi keybindings
• Quick column resizing without keybindings
• Faster cell selection in wide datasets
• More discoverable UI for new users

Considerations

• Textual framework has built-in mouse support — leverage existing primitives
• Must not interfere with terminal mouse selection (copy/paste) — consider a toggle or modifier key
• Mouse support should complement, not replace, keyboard navigation
• Whether to enable by default or opt-in via config