Maintain the capability matrix and prepare DATEX II 3.8 integration

[juherr]

Goal

Make version support explicit and ensure the next DATEX II model can be added without facade redesign.

Scope

• Generate a version by XML, JSON, validation, Exchange 2020, and profile matrix.
• Derive the matrix from automated tests and registry capabilities.
• Add a compatibility spike for DATEX II 3.8 model generation and discovery.
• Verify that adding 3.8 requires no XML, JSON, or validation facade signature changes.
• Document any standard-level incompatibilities.

Acceptance criteria

• The published capability matrix is generated from executable checks.
• Every advertised cell links to supporting tests or documented limitations.
• A 3.8 provider can be registered through the existing SPI.
• Existing facade signatures do not require version-specific additions.
• Generated sources remain unmodified.

Planning

• Priority: P2
• Complexity: L