Mostly Done. Code Review, Code Clean Up and PR Message remaining. I think I have the idea right, in both scala 2 and scala 3, extract the whole shape of Schema[A] and Schema[B], collect Handled, Provided as we go through the migration actions and compare.

both .build are compile time validation, and both do not require it to be inline.

/claim https://github.com/zio/zio-blocks/issues/519 /closes https://github.com/zio/zio-blocks/issues/519