Function movePlacementToIndex

movePlacementToIndex(
    pages: readonly PagePlacement[],
    fromPageNumber: number,
    toIndex: number,
): PagePlacementOperation | null
Converts the thumbnail list's (fromPageNumber, toIndex) drop coordinates into a stable placement-ID move. Returns null for an unchanged position.
Parameters
- pages: readonly PagePlacement[]
  The pages to process, in document order.
- fromPageNumber: number
  The from page number.
- toIndex: number
  The 0-based to index.
Returns PagePlacementOperation | null
The resulting page operation, or null when no move is needed.
- Defined in packages/colab/src/ui-operations.ts:52