* Fix distorted aspect ratio on Remove Background for iPhone portrait
photos by correcting EXIF orientation before upload
* Add readExifOrientation to read the EXIF orientation tag from JPEG
headers without loading the full image
* Add correctOrientation to redraw JPEG to canvas pre-upload, baking in
correct pixel orientation for the RemoveBackground API
* Gate orientation correction to mobile only — desktop JPEGs are
unaffected and incur no overhead
* Skip canvas re-encoding entirely if EXIF orientation is already
correct (value 1), avoiding unnecessary processing for screenshots and
pre-processed images

Resolves: [MWPW-199518](https://jira.corp.adobe.com/browse/MWPW-199518)

**Test URLs:**
- Before:
https://stage--da-cc--adobecom.aem.live/products/firefly/features/remove-background?unitylibs=stage
- After:
https://stage--da-cc--adobecom.aem.live/products/firefly/features/remove-background?unitylibs=MWPW-199518

**Testing Use Cases**
- Upload a recently taken iPhone portrait photo on adobe.com Remove
Background page on iPhone Safari (iOS 18.x) and verify the result image
is not distorted
- Upload the same photo on desktop browser and verify it processes
correctly with no regression
- Upload a PNG and WebP file on iPhone Safari and verify they are
unaffected by the change
- Upload a JPEG screenshot or downloaded image (no EXIF rotation) on
iPhone Safari and verify the canvas re-encoding step is skipped (result
should be identical to before)
- Upload a landscape iPhone photo and verify it processes correctly with
no distortion

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Co-authored-by: Sanjay Saravanan <saravana@adobe.com>