Preserve input vertices during polyhedron measurements

[antonsoo]

volume_polyhedron and centroid_polyhedron append temporary face centers to the input vertices when triangulating polygonal faces. Measuring a box changes its vertex count from 8 to 14; repeated measurements add unused vertices to subsequent meshes and OBJ exports. A tuple of vertices fails with AttributeError.

Copy the outer vertex sequence before appending temporary points. Coordinate objects, face data, triangulation order and numerical results stay unchanged.

Validation in the compas3 Conda environment:

• Eight new cases fail before the fix; four triangle controls pass. All 62 core tests pass afterward.
• Thirty native CAD workflows repeat measurements, build meshes and export/reload OBJ. All now preserve topology, avoiding 576 unused vertices. All 18 working controls and all 26 previously completed numerical streams are unchanged. Independent SciPy hull volumes and affine centers check the results.
• invoke test: 1023 passed, 12 skipped, using isolated local RPC ports. The original default-port invocation stalled at a socket read.
• Read-only source lint has the same two existing Rhino import-order findings on base and head. The unrelated automatic edits from invoke lint were restored.

What type of change is this?

• Bug fix in a backwards-compatible manner.

Checklist

• Added an Unreleased changelog entry and AUTHORS entry.
• Ran all tests with the local RPC port isolation described above.
• Whole-tree lint has no errors; two unchanged findings remain.
• Added tests that prove the fix.

OpenAI Codex assisted with investigation, implementation and validation.

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-19T19:50:22.787892Z	2c81d83	New commits

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Reviewed commit: 2d06b40726

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