Feature/native moonray spotlight

[gripeyes]

Compatibility:

minor

Issues/Tickets:

OpenMoonRay/openmoonray#276
#5

Release notes comment:

Added an optional native MoonRay SpotLight override to Houdini Solaris lights.

Comments for the reviewer:

This PR is stacked on Nick’s #5 update.

The Houdini parameter generator now adds a Native SpotLight tab to supported USD light types. Enabling the override switches the generated MoonRay class to SpotLight and exposes its projector-style controls inside that tab.

The controls are grouped under SpotLight and Falloff headings, including:

• Lens radius and aspect ratio
• Focal-plane distance
• Inner and outer cone angles
• Angle falloff type
• Black level

The standard Solaris Shaping tab remains the renderer-neutral USD ShapingAPI path.

This contains only the Python generator change. Generated .ds files and other derived artifacts are intentionally excluded.

Look or scene setup change:

Existing lights are unchanged unless the native MoonRay SpotLight override is explicitly enabled.

Special notes for production:

Generated Houdini parameter definitions must be refreshed after applying this change.

Depends on #5.

Attention/Reviewers:

@nshelton-dwa

AI Assisted Development:

Assisted-by: OpenAI Codex / GPT-5.6

Checklist:

• Documentation has been updated.
• Includes new unit tests.
• Includes new RATS tests.

[gripeyes]

A bit of reasoning behind this, it's partially a small redesign (it's necessary for Hou in this case) & the general "artist perspective/case" if I use that term. There's USDLux shaping, it's way more trimmed than the native Moonray spolight control-wise, why not expose it in a dedicated tab that's easy to use? Click a checkbox & get better controls.

visual exposure: