* Record attachment when recording new snapshots.

* fix

* Fix UIImage diffing to use portable DiffAttachment.data

UIImage's `Diffing.image()` used the deprecated `Diffing(toData:fromData:diff:)`
initializer which returns `[XCTAttachment]`. These get wrapped as
`DiffAttachment.xcTest(...)`, and in the Swift Testing code path the `.xcTest`
case is silently skipped — meaning image diff attachments are completely lost
on iOS/tvOS under Swift Testing.

Switch to the `.diff(toData:fromData:diffV2:)` factory method with
`DiffAttachment.data(pngData, name:)` cases, matching the NSImage pattern.

* Clean up and add test for UIImage.

* clean up

* update tests

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Co-authored-by: Brandon Williams <mbrandonw@hey.com>

…#1067)

* Prefer native Swift Testing image attachments on Xcode 26.4+

On Swift 6.3+ (Xcode 26.4+), CGImage/UIImage/NSImage/CIImage conform to
Attachable. Add a helper that detects .png attachment names and records
native image attachments instead of raw Data, enabling better Xcode
integration (preview, thumbnails). Falls back to data attachments on
older toolchains or for non-image data.

* clean up

* Fix Android.

---------

Co-authored-by: Brandon Williams <mbrandonw@hey.com>