Allow WhitespaceTrimmer to integrate with CropAround

This would enable 'cropping' to a specific aspect ratio using existing whitespace instead of re-adding it.

Start by locating the WhitespaceTrimmer and CropAround implementations and reading how their existing cropping and whitespace behavior interact. Define the integration needed to crop to a specific aspect ratio using existing whitespace, then verify that the behavior works without re-adding whitespace.

Written by the indexing model from the issue text.