Refactor Nonlinear CCD Implementation into a Class

[zfergus]

Description

• Introduced a new NonlinearCCD class to encapsulate nonlinear continuous collision detection (CCD) methods.
• Updated point-point, point-edge, edge-edge, and point-triangle CCD methods to use the new class structure.
• Modified the test cases to utilize the new NonlinearCCD class, ensuring consistency in the testing approach.
• Enhanced readability by applying consistent formatting and style changes across the CCD methods.
• Updated function signatures to accept Eigen::ConstRef types for better performance and clarity.
• Adjusted the conservative rescaling parameter handling in the CCD methods for improved accuracy.
• Removed deprecated function signatures and ensured all tests reflect the new method signatures.

Type of change

• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

[Copilot]

Pull request overview

This PR refactors nonlinear continuous collision detection (CCD) from a set of free functions into a NonlinearCCD class, updating C++ and Python call sites/tests and adjusting several signatures to use Eigen::ConstRef for consistency with the rest of the codebase.

Changes:

• Introduced ipc::NonlinearCCD (stateful tolerance/max-iterations/conservative-rescaling) and moved nonlinear CCD entry points onto it.
• Updated C++ tests and Python tests/bindings to call NonlinearCCD methods instead of the removed free functions.
• Updated tutorial snippet includes/signatures for interval arithmetic usage.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tests/src/tests/utils.hpp	Switch edge_normal args to Eigen::ConstRef.
tests/src/tests/test_has_intersections.cpp	Switch combine_meshes rotation args to Eigen::ConstRef.
tests/src/tests/ccd/test_point_edge_ccd.cpp	Switch helper arg types to Eigen::ConstRef<VectorMax3d>.
tests/src/tests/ccd/test_nonlinear_ccd.cpp	Update trajectory constructors to Eigen::ConstRef and migrate tests to NonlinearCCD.
src/ipc/ccd/nonlinear_ccd.hpp	Add NonlinearCCD class API and expose conservative piecewise-linear CCD as a static method.
src/ipc/ccd/nonlinear_ccd.cpp	Implement NonlinearCCD methods and refactor old free-function logic into the class.
python/tests/test_ccd.py	Update nonlinear CCD usage to instantiate/call ipctk.NonlinearCCD.
python/src/ccd/nonlinear_ccd.cpp	Replace module-level nonlinear CCD functions with NonlinearCCD Python class bindings.
docs/source/tutorials/nonlinear_ccd.rst	Update interval include path and example function signatures.

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[Copilot]

NonlinearCCD::point_triangle_ccd is the only CCD query in this class that is not declared virtual, unlike point_point_ccd, point_edge_ccd, and edge_edge_ccd. This asymmetry makes subclassing/overriding inconsistent and can be surprising for users extending the class. Consider making point_triangle_ccd virtual as well (or document why it is intentionally non-virtual).

[codecov]

Codecov Report

❌ Patch coverage is 95.45455% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 97.17%. Comparing base (5c5494c) to head (a8b5686).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
src/ipc/ccd/nonlinear_ccd.hpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #218      +/-   ##
==========================================
- Coverage   97.18%   97.17%   -0.01%     
==========================================
  Files         160      161       +1     
  Lines       24734    24748      +14     
  Branches      890      890              
==========================================
+ Hits        24037    24050      +13     
- Misses        697      698       +1     

Flag	Coverage Δ
unittests	97.17% <95.45%> (-0.01%)	⬇️

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