DCAB 0.25.0

Markup Compatibility choice requirement

• Adds a 36th deterministic fixture pair for an OOXML Markup Compatibility (MCE) Choice/@requires transition.
• Holds one AlternateContent, one Choice, one Fallback, the package-member set, and all stored Word text fixed; only the private required-feature prefix changes.
• Extends the optional DocFence adapter for DocFence 0.35 aggregate MCE evidence and updates its CI dependency to that paired tag.

Verification

• Regenerated and structurally validated both repository and bundled fixture trees.
• Built and checked wheel and sdist; each validates in a fresh environment.
• The independently installed DocFence 0.35 and DCAB 0.25 artifacts strictly score 36/36 cases.

The new fixture is static only: it does not validate MCE conformance, resolve a prefix, choose a branch, target an Office version, preprocess or save a package, or make a client-rendering claim.