Build an Excel-like grid with keyboard navigation

• A grid of cells (for example 20 rows by 10 columns) with column letters and row numbers; one active cell is highlighted
• Arrow keys move the active cell; Tab and Shift+Tab move right and left; Enter moves down; movement stops at the edges
• Typing on a selected cell, or pressing F2 or Enter, starts editing; Enter commits and moves down, Escape cancels, and clicking another cell commits
• Shift plus arrows or mouse dragging selects a rectangular range that is highlighted, with the active cell as the anchor
• Copy (Ctrl or Cmd+C), Cut and Paste work on the selected range using tab-separated text through the clipboard events, and pasting a block fills cells from the active cell
• Delete clears the contents of the selected range; the grid is exposed with role="grid" and the active cell has aria-selected

Only after every requirement works.

• Column resizing and sticky headers
• Undo and redo
• Fill handle that drags a value or series down