Return complete FIRST Global match details

[jameslockman]

Summary

• Deserialize the upstream FIRST Global details object without a fixed season-specific schema.
• Include the full raw object as nested details in each scores response, while retaining common alliance summaries and the existing flattened passthrough for new-season fields.
• Update score endpoint documentation.

Validation

• dotnet build gatool-api.csproj --no-restore
• Smoke-tested deserialization and conversion to ensure all sample detail properties survive in the nested output.
• git diff --check