[4.6.0] fix: include SDK root in local CMake prefixes

[wyli]

Bug use case

With the Holoscan SDK installed at its default /opt/nvidia/holoscan prefix, a standalone C++ Module that uses find_package(holoscan) can fail during either of these local workflows:

holoscan build <module> --local
holoscan package <module> --local

The 4.6 CLI passes /opt/nvidia/holoscan/lib as the CMake installation prefix. That starts CMake's package search one level too deep, so it may not discover the SDK configuration under <prefix>/lib/cmake/holoscan.

Fix

• Pass the SDK root first in CMAKE_PREFIX_PATH.
• Retain <sdk-root>/lib as a secondary compatibility prefix.
• Share the same prefix construction between local build and package paths, matching the behavior on main.

Validation

• Existing focused unit tests: 46 passed.
• Built a generated standalone C++ Module locally against Holoscan SDK 4.6.0.
• Packaged the generated Module locally as a DEB.

No unit tests were added.

AI-assisted: Created with Codex/GPT at the user's request.

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[tbirdso]

@wyli is this a cherry-pick of an existing commit? Could you provide the origin reference?

[wyli]

@wyli is this a cherry-pick of an existing commit? Could you provide the origin reference?

the fix is part of a large new feature commit 655a34b, not feasible to directly cherrypick