Method shift

restored-src/src/ink/output.ts:219–221

* Shift full-width rows within [top, bottom] by n. n > 0 = up. Mirrors * what DECSTBM + SU/SD does to the terminal. Paired with blit() to reuse * prevScreen content during pure scroll, avoiding full child re-render.

(top: number, bottom: number, n: number)

   * prevScreen content during pure scroll, avoiding full child re-render.
   */
  shift(top: number, bottom: number, n: number): void {
    this.operations.push({ type: 'shift', top, bottom, n })
  }

  /**
   * Clear a region by writing empty cells. Used when a node shrinks to