API /sdapi/v1/extra-single-image returns unchanged image (upscaler ignored)

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Environment
Forge (latest)
Windows
Endpoint: /sdapi/v1/extra-single-image
**Problem**

The Extras API does not perform any upscaling.

Request returns HTTP 200
Response contains a valid image
Output image is identical to input

No resizing, no processing, no error.

**Reproduction**

Request payload:

{
"image": "",
"resize_mode": 1,
"upscaling_resize": 2,
"upscaler_1": "Lanczos"
}

**Verification**
Input and output file size are identical
Image resolution does not change

**Expected Behavior**

Image should be upscaled according to upscaling_resize.

**Actual Behavior**

API returns the original image unchanged.

**Notes**
Tested with different upscalers
Base64 encoding verified
No errors returned by API
Fully reproducible

Start at the /sdapi/v1/extra-single-image endpoint and reproduce the request with resize_mode 1, upscaling_resize 2, and upscaler_1 set to Lanczos. Trace why the response preserves the input dimensions, then add or update a regression test if the API test location is identified; done means the response is resized and processed according to the requested upscaler.

Written by the indexing model from the issue text.