Reshape data between long and wide formats.
Tab / Shift+Tab: Move focus
Left / Right: In tab bar: Switch Pivot and Melt.
In text fields: Move cursor
↑ / ↓: Change selection (index, pivot, value, aggregation, strategy, etc.)
Space: Toggle index/explicit list; toggle Sort new columns (Pivot)
Enter: Apply, or Cancel/Clear when focused
Esc: Close without applying
? / F1: Show this help (F1 works in text fields)
Pivot: long → wide (index, pivot col, value col, aggregation).
Melt: wide → long (index, strategy, variable/value names).