Preserve zero descriptors in RootSIFT normalization - #4891

## Summary

Merge upstream 9371f7b and PR4895
maintainer revision db7586c into
d297c1e, retaining independent stream,
blocking-sync, LoMa resize/transfer and ONNX stream changes.

Retain upstream option initialization, CUDA diagnostics and RootSIFT zero-row
safety. Use the maintainer's generic fail-closed BF16 helper and thin LoMa
wrapper. Register CUDA tests once, keep their CUDA dependency explicit, and
fix the sparse-matrix test's mixed CMake link signature.

## Validation

Incremental over d297c1e; retained the imported merge parents.

22 affected CPU objects compiled and CLI linked incrementally;
63 focused CPU tests and 7 RTX3080Ti CUDA tests pass, zero skips/failures.
Actual separate CUDA-enabled CMake configure/generation passes. The initial
ONNX test-link and Poisson CMake failures were corrected; only outstanding
test links were completed, with no repeated CLI or object build.

The one-line Poisson test CMake fix was configured after native tests and
changes no compiled production code. Public formatting changes whitespace
and include ordering only. CUDA objects are reused for declaration/comment
header deltas. Nine inherited archive identities match qualified controls;
the remaining inputs inherit the frozen native-build link closure.

No performance, memory, whole-scene quality, HIP, Python-binding or
unsupported-device end-to-end LoMa claim. PR4895 remains unmerged upstream.

AI disclosure: Totally vibe coded.

## Upstream commits

- `5ff7e73c4efa1fcad0a7766f0242ed8cec700831` Avoid lambdas as default member initializers in feature options (MSVC ODR violation) (colmap#4900)
- `3dd12895f96ae88f43eb7cfee8b26c467c6954e1` Fix CLI option names in the feature and FAQ docs (colmap#4901)
- `15526bb9a7bca6d1843b8b849169d7f6ce4f900b` Improve CUDA driver failure diagnostics (colmap#4903)
- `9371f7b47ebe660dfa8a8d968ff8def199ef0456` Preserve zero descriptors in RootSIFT normalization (colmap#4891)