feat(triangulation): restore optional parallel insertion and removal

[acgetchell]

• add an opt-in CGAL/TBB production configuration
• preserve lock-grid ownership across copies, moves, swaps, and snapshots
• align Codecov line accounting with LCOV coverage

Summary by CodeRabbit

• New Features

  • Added an opt-in build option to enable CGAL parallel triangulation via TBB.
  • Preserved lock-grid ownership/behavior across triangulation construction, copy, move, and detaching.
  • Added a dedicated parallel triangulation test run (including ASan parallel scenarios).

• Documentation

  • Updated CI/CTest expectations and reference-suite entry counts.
  • Refined Coverage/Codecov guidance and clarified sanitizer behavior for parallel vs sequential runs.

• Tests

  • Added a parallel triangulation test covering correctness and lock ownership semantics.
  • Added a public API compile-time compatibility check.

• Chores

  • Updated Codecov parsing to treat partial LCOV branch hits as hits.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between d4dabbe and 35b241e.

📒 Files selected for processing (4)

• CMakeLists.txt
• CMakePresets.json
• README.md
• tests/CMakeLists.txt

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Walkthrough

The PR adds opt-in CGAL TBB support for parallel triangulation, introduces lock-grid-owning triangulation state, updates foliated triangulation operations and snapshots, adds dedicated tests, and aligns CTest, README, and Codecov configuration.

Changes

Parallel triangulation support

Layer / File(s)	Summary
Build and test target wiring CMakeLists.txt, CMakePresets.json, src/CMakeLists.txt, tests/CMakeLists.txt	Adds opt-in CGAL TBB configuration, removes direct TBB linkage from existing targets, enables the path in the ASAN preset, and registers a dedicated parallel triangulation test.
Lock-grid ownership state include/Foliated_triangulation.hpp	Adds locking-box helpers and Delaunay_state to own, validate, transfer, and detach CGAL lock data structures.
Foliated triangulation integration include/Foliated_triangulation.hpp	Routes construction, mutation, validation, collection, swapping, and snapshots through the wrapped triangulation state.
Parallel validation and contracts tests/Parallel_triangulation_test.cpp, tests/Public_api_consumer.cpp, README.md, .codecov.yml	Adds compile-time and runtime ownership tests, updates documented CTest and sanitizer behavior, validates the public construction API, and configures LCOV partials as hits.

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
  participant ASAN
  participant CMake
  participant DelaunayState
  participant FoliatedTriangulation
  participant ParallelTest
  ASAN->>CMake: enable ENABLE_PARALLEL_TRIANGULATION
  CMake->>DelaunayState: configure CGAL::TBB_support
  ParallelTest->>DelaunayState: construct and transfer lock-owned state
  DelaunayState->>FoliatedTriangulation: provide wrapped triangulation
  FoliatedTriangulation->>DelaunayState: create detached snapshot
  ParallelTest->>FoliatedTriangulation: validate ownership and snapshot state

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Possibly related issues

• Fix parallel insertion/deletion into Delaunay triangulations #74 — Covers parallel Delaunay insertion/deletion, lock ownership, configuration, and testing addressed by this PR.
• Restore and validate multithreaded C++ support #88 — Describes the opt-in CGAL/TBB parallel triangulation capability implemented and tested here.

Possibly related PRs

• acgetchell/CDT-plusplus#100 — Introduces related FoliatedTriangulation<3> and make_triangulation infrastructure in the same core header.
• acgetchell/CDT-plusplus#111 — Overlaps the FoliatedTriangulation<3> ownership, constructor, mutation, and snapshot changes.

Poem

Lock grids hold the points in place,
TBB gives threads a faster pace.
States move safely, snapshots clear,
Tests make every binding dear.
Parallel paths now build and run—
Triangulation’s work is done!

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly reflects the main change: restoring optional parallel triangulation insertion and removal.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/74-parallel-triangulation

Warning

There were issues while running some tools. Please review the errors and either fix the tool's configuration or disable the tool if it's a critical failure.

🔧 Checkov (3.3.8)

CMakePresets.json

Traceback (most recent call last):
File "/usr/local/bin/checkov", line 2, in
from checkov.main import Checkov
ModuleNotFoundError: No module named 'checkov'

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@CMakeLists.txt`:
- Around line 138-144: Make the CGAL TBB dependency conditional on
ENABLE_PARALLEL_TRIANGULATION: move the CGAL::TBB_support availability guard and
any TBB discovery or parallel-test wiring into that option’s branch, while
allowing configuration to proceed without TBB when parallel triangulation is
disabled. Preserve the existing fatal error when parallel triangulation is
explicitly enabled but CGAL::TBB_support is unavailable.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yaml

Review profile: ASSERTIVE

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📥 Commits

Reviewing files that changed from the base of the PR and between c7d6a35 and d4dabbe.

📒 Files selected for processing (8)

• .codecov.yml
• CMakeLists.txt
• README.md
• include/Foliated_triangulation.hpp
• src/CMakeLists.txt
• tests/CMakeLists.txt
• tests/Parallel_triangulation_test.cpp
• tests/Public_api_consumer.cpp

💤 Files with no reviewable changes (1)

• src/CMakeLists.txt