Align dependency packages with Houdini 21

[gripeyes]

Compatibility:

build

Issues/Tickets:

My original (a bit broader) commit, it has also been related to when I was implementing color management into moonray through OCIO & the OCIO update was a necessity, so I've tried to align the required compatible dependency stack. Qt update was causing gui issues, but it's not a necessary update for solaris/hydra.

Release notes comment:

Aligned the bundled macOS dependency packages with Houdini 21-era build requirements.

Comments for the reviewer:

This PR extracts the macOS dependency-toolchain updates from historical commit a2216e1 that are still missing from current upstream main.

Updated packages:

• Boost 1.78.0 → 1.85.0
• OpenSubdiv 3.5.0 → 3.6.0
• OpenEXR 2.5.7 → 3.3.2
• Added standalone Imath 3.1.12 for OpenEXR 3
• oneTBB 2020 U3 → 2022.1.0
• OpenVDB 9.1.0 → 12.0.1
• OpenColorIO 2.0.2 → 2.4.1
• OpenImageIO 2.3.20.0 → 2.5.18.0

Required build adjustments are included:

• OpenEXR 3 now uses the standalone Imath package.
• oneTBB uses its newer CMake build and installation flow.
• OpenImageDenoise removes bundled versioned TBB libraries before installation so they cannot replace the separately built oneTBB.
• OpenImageIO is configured against the refreshed Imath, OpenEXR, OpenColorIO, and oneTBB packages.
• Existing upstream CMake 4 compatibility handling and download verification are preserved.

This is intentionally limited to the bundled macOS dependency stack. It does not change:

• Qt or MoonRay GUI configuration
• Houdini installation paths
• Houdini or macOS presets
• Python version or path handling
• Setup scripts
• Submodule revisions
• hdMoonRay, SDR, MoonRay, or Moonshine USD source
• Unrelated macOS fixes

The packages are aligned with the versions needed by the Houdini 21-era toolchain, but the PR does not introduce a direct dependency on a particular Houdini installation.

Look or scene setup change:

No expected look or scene setup changes.

Special notes for production:

The macOS third-party dependencies must be rebuilt after this change. Existing dependency installations should not be mixed with the refreshed dependency stack.

Attention/Reviewers:

AI Assisted Development:

Assisted-by: OpenAI Codex / GPT-5.6

Checklist:

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

No documentation, unit-test, or RATS changes are included because this PR is limited to the macOS dependency build definition.

[gripeyes]

Mentioning this PR since they go hand-in-hand (TBB version & macOS)
#274

[gripeyes]

In human words, I was bumping up my h20.5 massive PR into h21 algined dependencies. The build suceeded simply said. TBB update can be skipped in correlation w/ the atmoic/GPU PR. Haven't tried building it yet with the latest hdmoonray & CMake update. AI gen review on this PR:

Compatibility note: CMake configuration and generation succeed on AppleClang arm64, but a full third-party and MoonRay rebuild has not been completed.

oneTBB 2022.1 removes legacy APIs still referenced by current MoonRay sources, notably tbb/task_scheduler_init.h. OpenMoonRay/moonray#37 addresses the isolated tbb::atomic use in MetalGPUAccelerator, but it does not migrate all remaining legacy TBB APIs.

I have intentionally left the oneTBB update in this PR for review as part of the Houdini 21-era dependency alignment. If maintainers prefer this PR to remain immediately buildable without additional TBB migration work, I can restore TBB to 2020_U3 while retaining the other dependency updates.