feat(protocol): support AdCP 3.1.13 schemas

[bokelley]

Summary

• update the SDK protocol pin from AdCP 3.1.10 to 3.1.13
• regenerate the verified schema bundle and generated models
• refresh the canonical mapping registry to v1.3.1 and document its 3.1 pixel-density preservation boundary
• re-vendor and re-pin request-signing vectors from the 3.1.13 release

The generated type report shows no field-shape changes, and the signing vectors are byte-identical to the 3.1.10 set.

Validation

• protocol bundle checksum and Sigstore verification passed
• focused schema, codegen, canonical projection, signing, and version tests: 260 passed, 1 skipped
• full suite: 6259 passed, 41 skipped, 9 deselected, 1 xfailed
• Ruff, Black, mypy, Bandit, and repository pre-commit hooks passed

[aao-ipr-bot]

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