Minimal QR scan test: preserve size and contrast

For a QR Scanner problem, make a harmless code that preserves the likely cause: small printed size, low contrast, glare, damage, or a dense payload. State the expected decoded text and test it with the same camera and distance as the real use. A large high-contrast code may scan perfectly while the actual label fails. Avoid using live login or payment codes as samples. Compare the scanned payload, not merely whether the camera recognized a square.