Houdini 20.5 Solaris build/testing integration

[rolledhand]

This is a building/testing integration branch for OpenMoonRay/openmoonray#228.

Summary:

• Keeps hdMoonrayAdapters enabled and builds them against Houdini 20.5/USD 24.03 with a target-local compatibility shim for the current macOS toolchain.
• Adds Houdini/Solaris prim-type normalization, including DomeLight schema variants.
• Applies initial husk render settings delivered through HdRenderSettingsMap.
• Hardens primvar/user-data handling and material value conversion paths used by the H20.5 fixtures.
• Adds focused H20.5 fixtures for adapters, DomeLight, RenderVar/AOV auditing, and MoonRay material-builder smoke tests.

Validation:

• cmake --preset macos-houdini-release
• cmake --build /Applications/MoonRay/build --target hdMoonrayAdapters --config Release --verbose
• cmake --build --preset macos-houdini-release
• husk smoke fixtures for DomeLight and MoonRay material builder RDL output.