perf(validation): certify Level 4 realization fast paths

[acgetchell]

• Preserve exact active-set classification for degenerate simplex pairs and verify optimized agreement across random and boundary cases in 2D–5D.
• Add focused narrow-phase and whole-realization benchmarks with stable IDs to local and release comparison workflows.
• Add an isolated large-scale Level 4 validation mode.
• Add scoped Cargo and uv update recipes, refresh dependency locks, and pin rumdl 0.2.55.

Closes #482

[coderabbitai]

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Reviewing files that changed from the base of the PR and between f752da2 and 90c79da.

📒 Files selected for processing (2)

• scripts/tests/test_justfile_discoverability.py
• src/geometry/util/simplex_lp.rs

🚧 Files skipped from review as they are similar to previous changes (2)

• scripts/tests/test_justfile_discoverability.py
• src/geometry/util/simplex_lp.rs

---

Walkthrough

The PR adds Level 4 realization-validation benchmarks, integrates them into benchmark and release workflows, improves degenerate simplex intersection handling, adds cross-check tests, introduces a realization-only debug scope, and adds repository update recipes.

Changes

Realization validation

Layer / File(s)	Summary
Degeneracy-aware intersection classification src/geometry/realization.rs, src/geometry/util/simplex_lp.rs	The validator checks simplex degeneracy before confinement, uses legacy active sets when needed, and compares optimized results with the legacy oracle across dimensions 2–5.
Level 4 benchmark coverage Cargo.toml, benches/realization_validation.rs, benches/README.md, scripts/benchmark_utils.py, scripts/tests/test_benchmark_utils.py, .github/workflows/release-benchmarks.yml, justfile, docs/architecture/project_structure.md, docs/dev/commands.md	The new Criterion benchmark measures shared-face and whole-triangulation realization validation. Benchmark targets, stable IDs, release baselines, curated suites, and documentation now include it.
Large-scale realization validation scope tests/large_scale_debug.rs	The debug test accepts the realization scope and runs Level 4-only validation through is_valid_realization.

Repository maintenance workflows

Layer / File(s)	Summary
Repository update workflows justfile, docs/dev/commands.md, scripts/tests/test_justfile_discoverability.py	The repository adds update, update-cargo-tools, and update-dependencies recipes, documents them, updates the rumdl pin, and tests their command composition.

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

Merge Risk: ⚪ Minimal · up to 90c79

The PR adds validation, benchmarking, and dependency workflow updates without any supplied current-head correctness or operational issue; no actionable merge-blocking risk remains.

Sequence Diagram(s)

sequenceDiagram
  participant BenchmarkRunner
  participant RealizationValidator
  participant SimplexLP
  BenchmarkRunner->>RealizationValidator: validate benchmark fixture
  RealizationValidator->>SimplexLP: classify simplex intersections
  SimplexLP-->>RealizationValidator: return intersection classifications
  RealizationValidator-->>BenchmarkRunner: report validation result

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Possibly related issues

• Standardize release benchmarking and retain analysis-ready evidence causal-triangulations#184: The issue concerns the shared release-benchmark and curated baseline infrastructure that this PR extends with realization-validation coverage.

Possibly related PRs

• acgetchell/delaunay#531: Both modify realization intersection classification and active-set paths.
• acgetchell/delaunay#515: This PR extends the realization-validation refactor with benchmarks and regression coverage.
• acgetchell/delaunay#542: Both update release-signal benchmark coverage and certified realization validation.

Suggested labels: enhancement, rust, geometry

Poem

I hop through simplices, precise and bright,
Degenerate faces now classify right.
Benchmarks bloom from two dimensions to five,
Release baselines keep checks alive.
Update recipes stay neatly in tune. 🐇

🚥 Pre-merge checks | ✅ 3 | ❌ 2

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Linked Issues check	⚠️ Warning	The PR adds tests and benchmarks, but the summary does not show the required fraction-free exact solver or separating-axis early exit from issue #482.	Implement or document the required fraction-free exact sign path and certified disjointness early exit, and provide evidence for the issue's performance target and unchanged periodic behavior.
Out of Scope Changes check	⚠️ Warning	The new Cargo and uv update recipes, dependency-lock refresh, and rumdl version pin are unrelated to the Level 4 validation objective in issue #482.	Move repository maintenance and tool-update changes to a separate pull request, or link them to an issue that explicitly requires them.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the Level 4 realization-validation performance change and its fast-path focus.
Description check	✅ Passed	The description directly covers the validation changes, benchmarks, tooling, and isolated Level 4 mode in the changeset.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 100.00%.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch perf/482-realization-validation-benchmark

---

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[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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🟢 Metrics 33 complexity

Metric	Results
Complexity	33

View in Codacy

🟢 Coverage 99.38% diff coverage · +0.22% coverage variation

Metric	Results
Coverage variation	✅ +0.22% coverage variation (-1.00%)
Diff coverage	✅ 99.38% diff coverage

View coverage diff in Codacy

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (c76f826)	81860	74783	91.35%
Head commit (90c79da)	82009 (+149)	75102 (+319)	91.58% (+0.22%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#559)	161	160	99.38%

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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[coderabbitai]

Actionable comments posted: 1

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Inline comments:
In `@scripts/tests/test_justfile_discoverability.py`:
- Around line 153-163: Extend the assertions for dependency_update in the test
covering update-dependencies so it also rejects unrestricted “uv tool upgrade”
and “cargo install-update --all” commands, matching the existing checks for
tool_update while preserving the allowed dependency commands.

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---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Path: .coderabbit.yml

Review profile: CHILL

Plan: Pro

Run ID: ae62a120-2db9-4ba7-8f08-3f9fb3077e6a

📥 Commits

Reviewing files that changed from the base of the PR and between c76f826 and f752da2.

⛔ Files ignored due to path filters (2)

• Cargo.lock is excluded by !**/*.lock
• uv.lock is excluded by !**/*.lock

📒 Files selected for processing (13)

• .github/workflows/release-benchmarks.yml
• Cargo.toml
• benches/README.md
• benches/realization_validation.rs
• docs/architecture/project_structure.md
• docs/dev/commands.md
• justfile
• scripts/benchmark_utils.py
• scripts/tests/test_benchmark_utils.py
• scripts/tests/test_justfile_discoverability.py
• src/geometry/realization.rs
• src/geometry/util/simplex_lp.rs
• tests/large_scale_debug.rs

[codecov]

Codecov Report

❌ Patch coverage is 99.37888% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 91.55%. Comparing base (c76f826) to head (90c79da).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/geometry/util/simplex_lp.rs	99.30%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #559      +/-   ##
==========================================
+ Coverage   91.33%   91.55%   +0.22%     
==========================================
  Files          88       88              
  Lines       81649    81798     +149     
==========================================
+ Hits        74574    74893     +319     
+ Misses       7075     6905     -170     

Flag	Coverage Δ
unittests	91.55% <99.37%> (+0.22%)	⬆️

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