Add opt-in transform orthonormalization to the Collada importer

[Renanse]

What

Adds ColladaImporter.setOrthonormalizeTransforms(boolean) (off by default). When enabled, the rotational upper-left 3×3 of every baked node and animation-channel transform is cleaned with Matrix4.orthonormalizeLocal() (Gram-Schmidt, added in #137) right before it becomes a Transform — preserving the translation column.

Wiring:

• New flag on ColladaImporter, following the existing setLoadTextures/setFlipTransparency pattern.
• Applied at the two fromHomogeneousMatrix choke points: ColladaNodeUtils.getNodeTransforms (node/joint transforms) and ColladaAnimUtils.bakeTransforms (animation samples).
• ColladaAnimUtils is now handed the ColladaImporter in its constructor so it can read the flag, mirroring how ColladaNodeUtils and ColladaMaterialUtils already take it.

Why

Autodesk FBX→Collada and OpenCollada exporters frequently bake enough floating-point rounding error into <matrix> transforms that the 3×3 rotational block fails isOrthonormal(). On skeletal import this trips the long-standing "supplied transform with non-rotational matrices. May have unexpected results." warning flood and degrades the rotation extracted for each channel. This gives users a one-call opt-in to clean those matrices at import. Addresses the importer half of #32.

Design notes

• Opt-in on purpose. Orthonormalizing discards any scale/shear baked into a <matrix>, and we can't tell intentional shear from rounding noise — so it's off by default and documented as "only enable when your source encodes pure rotation + translation." This matches the conclusion reached in the Resolve Non-rotational matrices at import time in Animation Manager from collada #32 discussion (don't auto-enforce).
• Best-effort, never fatal. A genuinely rank-deficient block (e.g. a collapsed/zero-scale transform) makes orthonormalizeLocal() throw ArithmeticException; that's caught per-transform and the matrix is left as-is with a warning, rather than aborting the whole load.

Tests

New TestColladaOrthonormalize loads an inline .dae whose single node carries a slightly-skewed near-identity <matrix> plus a translation:

• off by default → the node's transform reports a non-rotational matrix (current behavior preserved).
• enabled → the 3×3 is orthonormal (isRotationMatrix() true) and the (5, 6, 7) translation is preserved.

Full ardor3d-collada suite green (7 tests, 0 failures). The node path is covered directly; the animation-channel path shares the identical mechanism at the sibling choke point.

Follow-up

Depends on #137 (merged). Issue #32 can be closed once this lands; I'll leave the issue comment to you.

🤖 Generated with Claude Code

Update: temp-pool cleanup

Folded in a fix for a pre-existing leak in the two methods this PR already touches: bakeTransforms and getNodeTransforms each fetched two Matrix4.fetchTempInstance() temps and never released them. Their bodies are now wrapped in try/finally so both temps are returned to the per-thread pool on all paths (including exceptions). finalMat is still consumed by fromHomogeneousMatrix in the return expression before the finally runs, so there is no use-after-release.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 4564061b-8a61-429e-af5f-66cef54f8956

📥 Commits

Reviewing files that changed from the base of the PR and between c299b50 and e1e2092.

📒 Files selected for processing (4)

• ardor3d-collada/src/main/java/com/ardor3d/extension/model/collada/jdom/ColladaAnimUtils.java
• ardor3d-collada/src/main/java/com/ardor3d/extension/model/collada/jdom/ColladaImporter.java
• ardor3d-collada/src/main/java/com/ardor3d/extension/model/collada/jdom/ColladaNodeUtils.java
• ardor3d-collada/src/test/java/com/ardor3d/extension/model/collada/jdom/TestColladaOrthonormalize.java

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch collada-orthonormalize

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