Extend the 10,000-pixel limit for extend() to standard dimension limit

The 10,000-pixel limit added to extend() in Sharp 0.35.3 is blocking us from upgrading. Our workflow needs larger padding values, and these have worked fine in previous versions.

Here’s a simple example:

await sharp({
  create: {
    width: 1,
    height: 1,
    channels: 3,
    background: 'white'
  }
})
  .extend({ left: 20000, background: 'black' })
  .png()
  .toBuffer();

This only produces a narrow, 20,001-pixel image, but the new validation rejects it.

I found the commit that introduced this, but couldn’t find any discussion about why 10,000 was chosen. Is there a technical reason for that number?

Protective defaults make sense, but this feels like an arbitrary cutoff without a way around it. Neither limitInputPixels: false nor unlimited: true bypasses it.

Could we have a way to raise or disable this limit, similar to limitInputPixels?