Add colmap-review agent skill for code review - #4934

Integrate thirteen official upstream commits after the private GPU cleanup
checkpoint. Preserve blocking host-sync selection and its CUDA 12.0/12.1
flag boundary while adopting upstream's generalized compute-capability
helper and LoMa/FlexGlue callers. Keep both capability and policy tests;
remove the duplicate colmap_util_cuda link from automatic composition.

Includes upstream rig-frame covisibility, thin bitmap thumbnails, visibility
coordinate conversion, row-wise warp dispatch, benchmark fixes, FlexGlue,
review guidance, and the Windows non-GUI SIFT-test build fix.

Validation at this private checkpoint: merge conflicts resolved in cuda.cc,
cuda.h, cuda_test.cc; source search found no remaining old BF16-helper call;
git diff --check passed. Native merged-source qualification and independent
exact-diff review remain pending. Prior GPU tests qualify their pinned source,
not this entire merged product. No reconstruction or performance claim.

AI-assisted integration. Existing published history is preserved.

## Upstream commits

- `e52aa8ee12ef58eb1cd16ada2be9316fa1c02cd3` Move pycolmap macOS CI from macos-14 to macos-15 runner (colmap#4933)
- `8007d1a51ae0c0af87fff3ebd204cf4698df7565` Preserve float weight ordering in maximum spanning trees (colmap#4928)
- `dd84102ef5e75fc17e20da281d2fc2fee5aca6a9` Bump pypa/gh-action-pypi-publish from 1.14.2 to 1.14.3 in /.github/workflows (colmap#4942)
- `721e185ddb6205b85fddc39ccf0774567f6be6ed` Add FlexGlue feature matcher (colmap#4908)
- `d0a411f2a9af139b5ea8118d64e5da5b70c6a890` FlexGlue: cache the dense features on the GPU (colmap#4915)
- `105817b6299cf22144fbbf39f95689681352476d` Hoist camera model dispatch per row in image warps (colmap#4935)
- `27ffad4388ce5647df3ea9e547bf8e1ea155fbcd` Make benchmark translation-angle errors invariant to reconstruction scale (colmap#4932)
- `e8f3522b936882cbceae074a19fca58fe378d323` Resolve benchmark paths before changing subprocess directories (colmap#4931)
- `f664d5d219230c1f1ebf9c2c7ecdcafc451b95ce` Clamp visibility coordinates before unsigned conversion (colmap#4943)
- `138119b7640d46f1f51fe329694a9ddae3ae0908` Keep thin bitmap thumbnails nonempty (colmap#4927)
- `b16ed5f97fa405ff2462745f9509386a9ebe6ece` Count rig frame covisibility once per 3D point (colmap#4893)
- `93dbbcb7f3019da30bd4a2c72753421e6cb85b45` Add colmap-review agent skill for code review (colmap#4934)
- `2a6f6955ed73a3d15b2a75edede5750e7c7b3304` Fix sift_test build on MSVC without the GUI (colmap#4955)

Integrate thirteen official upstream commits after the private GPU cleanup
checkpoint. Preserve blocking host-sync selection and its CUDA 12.0/12.1
flag boundary while adopting upstream's generalized compute-capability
helper and LoMa/FlexGlue callers. Keep both capability and policy tests;
remove the duplicate colmap_util_cuda link from automatic composition.

Includes upstream rig-frame covisibility, thin bitmap thumbnails, visibility
coordinate conversion, row-wise warp dispatch, benchmark fixes, FlexGlue,
review guidance, and the Windows non-GUI SIFT-test build fix.

Validation at this private checkpoint: merge conflicts resolved in cuda.cc,
cuda.h, cuda_test.cc; source search found no remaining old BF16-helper call;
git diff --check passed. Native merged-source qualification and independent
exact-diff review remain pending. Prior GPU tests qualify their pinned source,
not this entire merged product. No reconstruction or performance claim.

AI-assisted integration. Existing published history is preserved.

## Upstream commits

- `e52aa8ee12ef58eb1cd16ada2be9316fa1c02cd3` Move pycolmap macOS CI from macos-14 to macos-15 runner (colmap#4933)
- `8007d1a51ae0c0af87fff3ebd204cf4698df7565` Preserve float weight ordering in maximum spanning trees (colmap#4928)
- `dd84102ef5e75fc17e20da281d2fc2fee5aca6a9` Bump pypa/gh-action-pypi-publish from 1.14.2 to 1.14.3 in /.github/workflows (colmap#4942)
- `721e185ddb6205b85fddc39ccf0774567f6be6ed` Add FlexGlue feature matcher (colmap#4908)
- `d0a411f2a9af139b5ea8118d64e5da5b70c6a890` FlexGlue: cache the dense features on the GPU (colmap#4915)
- `105817b6299cf22144fbbf39f95689681352476d` Hoist camera model dispatch per row in image warps (colmap#4935)
- `27ffad4388ce5647df3ea9e547bf8e1ea155fbcd` Make benchmark translation-angle errors invariant to reconstruction scale (colmap#4932)
- `e8f3522b936882cbceae074a19fca58fe378d323` Resolve benchmark paths before changing subprocess directories (colmap#4931)
- `f664d5d219230c1f1ebf9c2c7ecdcafc451b95ce` Clamp visibility coordinates before unsigned conversion (colmap#4943)
- `138119b7640d46f1f51fe329694a9ddae3ae0908` Keep thin bitmap thumbnails nonempty (colmap#4927)
- `b16ed5f97fa405ff2462745f9509386a9ebe6ece` Count rig frame covisibility once per 3D point (colmap#4893)
- `93dbbcb7f3019da30bd4a2c72753421e6cb85b45` Add colmap-review agent skill for code review (colmap#4934)
- `2a6f6955ed73a3d15b2a75edede5750e7c7b3304` Fix sift_test build on MSVC without the GUI (colmap#4955)

Refresh the experimental alternative with fork main while retaining its previous head as a parent. The resulting tree is exactly main plus the isolated shared-current-cost-cache deletion: one CUDA file, +1/-25.

## Change

Read the existing cost map directly during the ordered sampled-cost fold. Preserve current plane propagation, source packing, scheduling and fallback mathematics. The cache originates in custom a37c1c3, MVS: Reuse sampled current costs (GPU perf). The earlier alternative is retained through 8481f89; its original experiment was 8b1412f.

Historical Fountain11 photo+geometry at 3072 recorded 76.85 -> 78.82 seconds, one observation per arm, on the older revision. Retain this inconclusive/adverse observation with its earlier revision; current performance has not been measured. No performance experiment was reopened.

## Validation

- Exact candidate CUDA owner compiled with CUDA 13.2 for compute_86/sm_86. In a bounded retained-support context on RTX 3060, both matched targets passed all 13 selected cases: propagation, ordered source folding, checkpoint-HMM and paired-sweep preservation.
- Four complete inputs and four outputs matched across executables: 8,492,128 bytes per arm. Maps were finite with positive depth and checked ordered graph IDs. Complete witnesses use checkpoint_hmm=false; separate checkpoint tests cover both settings without full cross-executable true-mode witnesses.
- Direct owners, link maps and actual loaded providers were checked; managed jobs ended and released their bookings. Later host resize/warp changes have separate owner qualification. This is not a whole-branch build, reconstruction-quality, portability or current-performance result.

## Upstream commits carried forward

- e52aa8e Move pycolmap macOS CI from macos-14 to macos-15 runner (colmap#4933)
- 8007d1a Preserve float weight ordering in maximum spanning trees (colmap#4928)
- dd84102 Bump pypa/gh-action-pypi-publish from 1.14.2 to 1.14.3 in /.github/workflows (colmap#4942)
- 721e185 Add FlexGlue feature matcher (colmap#4908)
- d0a411f FlexGlue: cache the dense features on the GPU (colmap#4915)
- 105817b Hoist camera model dispatch per row in image warps (colmap#4935)
- 27ffad4 Make benchmark translation-angle errors invariant to reconstruction scale (colmap#4932)
- e8f3522 Resolve benchmark paths before changing subprocess directories (colmap#4931)
- f664d5d Clamp visibility coordinates before unsigned conversion (colmap#4943)
- 138119b Keep thin bitmap thumbnails nonempty (colmap#4927)
- b16ed5f Count rig frame covisibility once per 3D point (colmap#4893)
- 93dbbcb Add colmap-review agent skill for code review (colmap#4934)
- 2a6f695 Fix sift_test build on MSVC without the GUI (colmap#4955)
- 78cc729 Fix default prior_position_loss_scale to sqrt(chi2_95_3dof) (colmap#4936)
- 8653c6b Estimate two-view relative rotation covariance (colmap#4950)
- e1317dd FlexGlue: match keypoints in the resized descriptor input frame (colmap#4949)
- 3db6eb0 Extract ConvertPosePriorsToENU and skip pose priors without position (colmap#4937)
- 77cbe48 Store and estimate rotation covariances on PoseGraph (colmap#4951)
- 30a1a81 Support covariance whitening in CeresRotationAverager (colmap#4952)
- e6644e7 Fix -Wunused-result warning in ThreadPool::AddTask (colmap#4958)
- 5b6da88 Clear descriptor-index results for empty queries (colmap#4960)
- d1d92d9 Add COVARIANCE reweighting for Ceres rotation averaging (colmap#4953)
- 761d90d Enable covariance-weighted rotation averaging in global pipelines (colmap#4823)
- fdee2e1 Reuse the pose graph of GlobalPipeline in the component mappers (colmap#4912)

AI disclosure: Totally vibe coded