Updated softbinding-algorithm-list to include VSRMark

[mrappard]

Add VSRMark (com.cognitive-proof.vsrmark.1) — Unicode Variation Selector text watermark

This PR adds VSRMark, a text steganography algorithm developed by Cognitive Proof (https://cognitive-proof.com/), to
the soft binding algorithm list as identifier 39.

Algorithm summary

VSRMark hides a structured byte payload inside visible Unicode text by appending Unicode Variation Selectors
(U+FE00–U+FE0F and U+E0100–U+E01EF) after visible characters. Each hidden byte maps to exactly one variation selector,
making the encoded text visually identical to the original. The payload is wrapped in a self-describing block with a
magic identifier (VSR1), version number, big-endian payload length, and CRC32 checksum for integrity verification.

Submission checklist

• Entry conforms to softbinding-algorithm-list.schema.json
• All mandatory fields are present (identifier, alg, type, decodedMediaTypes, entryMetadata)
• identifier (39) is the next sequential value
• alg uses reverse-domain notation under the submitter's owned domain (cognitive-proof.com)
• informationalUrl is functional
• Submitter is a maintainer of the open-source algorithm

Reference implementation

https://github.com/Cognitive-Proof/VSRMark

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[domguinard]

hi @mrappard this addition will be discussed during today's C2PA watermarking task force meeting.

[domguinard]

Approved by the WM Taskforce during June 10 meeting.