feat: allow-browser-screenshot-config

[Perturbatio]

Currently Pest browser snapshot testing is a boolean check, it either precisely matches or it doesn't (via expect($actualImageBlob)->toMatchSnapshot(); )

This PR adds the ability to control the granularity of screenshot diffing and only fail if it exceeds the settings.

You can retain existing functionality with:

   // in Pest.php
    pest()->browser()->screenshotMaxDiffPixelRatio(0)
        ->screenshotMaxDiffPixels(0)
        ->screenshotThreshold(0);

The above will fail the test even if a single pixel is off (within Playwright's own internal tolerances).

If you want a little tolerance to account for some pixels not rendering consistently, you can do something like:

  // in Pest.php
  pest()->browser()
      ->screenshotMaxDiffPixelRatio(0.01)
      ->screenshotMaxDiffPixels(5)
      ->screenshotThreshold(0.3)

Larger numbers = more tolerance, the ratio is in the range of 0 to 1 and internally is a formula that determines the number of pixels allowed to vary by multiplying the expected width * height * maxDiffPixelRatio (which can result in very large tolerances)

Playwright will prefer the lower of the maxDiffPixelRatio or the maxDiffPixels

• added ability to control the screenshot diffing via screenshotThreshold, screenshotMaxDiffPixels and screenshotMaxDiffPixelRatio
• fixed issue with Pest assuming that if a screenshot does not precisely match (via base64 string comparison) that it has failed testing

[Perturbatio]

Note that other configuration options would be nice to have but I'm focussing on the ones which are most likely to affect most users atm.