feat(office): table detail panes and Alt+1/2/3 layout toggles

Add spreadsheet-style list, split detail pane with forms and document preview,
and Alt+1/2/3 to show/hide panes with even width distribution.

Co-authored-by: Cursor <cursoragent@cursor.com>

cmd/office/main.go

@@ -26,7 +26,7 @@ func main() {
 	}
 
 	m := ui.NewModel(client)
-	p := tea.NewProgram(m, tea.WithAltScreen())
+	p := tea.NewProgram(m, tea.WithAltScreen(), tea.WithMouseCellMotion())
 	if _, err := p.Run(); err != nil {
 		fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)