fix: stop Parse QR Code from participating in Magic (#2610)

[Sanjays2402]

Description

Parse QR Code declared a checks regex that matched any JPEG, PNG, GIF, WEBP or BMP magic bytes. Magic._generateOpCriteria (in src/core/lib/Magic.mjs) aggregates every operation that exposes a checks property and runs each against the input, so any image fed to Magic (which happens implicitly whenever Magic is in the recipe, including via the URL/QueryString demo) triggered a full QR parse. The QR decoder then logged [BGChefWorker]: Could not read a QR code from the image. to the browser console for every image that didn't contain a QR code.

This PR removes the this.checks array from ParseQRCode's constructor (leaving a comment that points at the issue). There is no cheap way to know an image contains a QR code without actually attempting to decode one, so it can't be a sensible Magic candidate. The operation itself is unchanged and every other operation is unaffected; only Magic's automatic dispatch stops attempting QR parsing. Users who know their image has a QR code can still add Parse QR Code to the recipe manually.

Behaviour before: loading the 1px-PNG demo URL from the issue with DevTools open prints [BGChefWorker]: Could not read a QR code from the image.
Behaviour after: same URL, console is silent; Magic still recognises the input as an image and lists the usual image-render suggestions.

Existing Issue

Fixes #2610.

Screenshots

No visual changes to CyberChef. The only observable difference is the absence of a console error message; no UI is affected.

AI disclosure

This change was written with the assistance of Claude. I have reviewed the diff and the test, understand the root cause and the fix, and take responsibility for the submitted code.

Test Coverage

Adds tests/node/tests/ParseQRCode.mjs with an API-level regression test asserting that OperationConfig["Parse QR Code"] declares no checks. The test fails on master with the original checks regex and passes with this change (verified both directions). The full node and operations suites still pass locally (255 and 2057 tests respectively).

[C85297]

@GCHQDeveloper581 @tomdev123 @np748293 would appreciate your views here. This operation has been part of magic for quite a long time (since #515 ). It doesn't seem to be an accident - it was specifically added, so we should be making a conscious decision if we are to remove it.

[GCHQDeveloper581]

I originally suggested removing it from Magic when I raised Issue #2610, and have given my rationale there (and the mitigation).

However, as more instances of Magic detection running amok are found - (#2410, #2642) I'm beginning to think that the correct response is to alter Magic to catch OperationError without reporting the error, and simply to remove the operation from consideration for that stage of the processing.