Make most dependencies private; document dependencies with graphviz

[zfergus]

Description

• Added a figure to the documentation for default dependencies of the ipc::toolkit library.
• Updated GraphViz configuration to include transparent backgrounds and Menlo font.
• Refactored BVH class to use unique_ptr to hide SimpleBVH
• Updated Sweep and Prune and Sweep and Tiniest Queue classes to use a Pimpl pattern for encapsulation.
• Change potential.tpp to potential.cpp file to hide implementation details.
• Update Abseil to 20250512.1

Type of change

• Enhancement (non-breaking change which improves existing functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
  • Potential breaking change if downstream libraries implicitly relied on previously public dependencies.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.24%. Comparing base (dbb1ab4) to head (c575980).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #183      +/-   ##
==========================================
- Coverage   96.25%   96.24%   -0.02%     
==========================================
  Files         104      105       +1     
  Lines        7991     8064      +73     
==========================================
+ Hits         7692     7761      +69     
- Misses        299      303       +4     

Flag	Coverage Δ
unittests	96.24% <100.00%> (-0.02%)	⬇️

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[Copilot]

Pull Request Overview

This PR refactors the ipc::toolkit library to make most dependencies private rather than public, reducing the exposure of implementation details to downstream consumers. It also adds GraphViz documentation showing the library's dependency structure.

• Implements Pimpl (Pointer to Implementation) pattern for BVH, SweepAndPrune, and SweepAndTiniestQueue classes
• Converts potential.tpp template implementation file to potential.cpp to hide implementation details
• Updates CMake configuration to make dependencies private and adds explicit dependencies for tests and Python bindings

Reviewed Changes

Copilot reviewed 21 out of 23 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tests/src/tests/candidates/test_normals.cpp	Improves test code with cleaner matrix initialization and clearer lambda parameter naming
tests/CMakeLists.txt	Adds explicit dependencies for libigl and OneTBB that tests require
src/ipc/potentials/	Converts template implementation to compiled source and adds required includes
src/ipc/broad_phase/	Implements Pimpl pattern to hide scalable_ccd and SimpleBVH dependencies
python/CMakeLists.txt	Adds explicit dependencies for Python bindings
docs/	Adds dependency graph documentation with improved GraphViz styling
CMakeLists.txt	Changes most dependencies from PUBLIC to PRIVATE linkage

Comments suppressed due to low confidence (1)

cmake/recipes/abseil.cmake:15

• The Abseil version '20250512.1' appears to be from May 2025, which is in the future relative to my knowledge cutoff of January 2025. Please verify this version exists or use a known stable version like '20240116.2'.

CPMAddPackage("gh:abseil/abseil-cpp#20250512.1")