Function reconstructPickPosition

reconstructPickPosition(
    mvpWorld: Mat4,
    viewportWidth: number,
    viewportHeight: number,
    xDev: number,
    yDev: number,
    depth01: number,
): PickedPosition | null
Reconstruct the geographic position of a picked pixel from its window depth.
Parameters
- mvpWorld: Mat4
  The frame's mercator-world → clip matrix (MapLibre's mainMatrix, f64).
- viewportWidth: number
  Pick-target width in DEVICE pixels (the drawing buffer).
- viewportHeight: number
  Pick-target height in DEVICE pixels.
- xDev: number
  Picked X in DEVICE pixels, top-left origin (same value given to pickWithDepth).
- yDev: number
  Picked Y in DEVICE pixels, top-left origin.
- depth01: number
  Window-space depth in [0, 1] from the pick pass.
Returns PickedPosition | null
The PickedPosition, or null when the matrix is singular or the result is degenerate (w ≈ 0).