Guard all mutating public API methods against post-finalization calls

[Copilot]

After any Erase* method is called, the triangulation is finalized and further mutation (vertex/edge insertion or additional erase calls) leads to silent index-out-of-range errors rather than a clear failure. This adds early, explicit rejection for all affected methods.

Changes

Triangulation.cs

• Added TriangulationFinalizedException (derives from TriangulationException) with a descriptive message
• Added IsFinalized guard at the top of every mutating public method: InsertVertices, InsertEdges, ConformToEdges, EraseSuperTriangle, EraseOuterTriangles, EraseOuterTrianglesAndHoles

TriangulationTests.cs

• Added one test per guarded method verifying TriangulationFinalizedException is thrown post-finalization (runs for both float and double via the shared base class)

Example

var cdt = new Triangulation<double>();
cdt.InsertVertices([...]);
cdt.EraseSuperTriangle(); // finalizes

// Previously: silent IndexOutOfRangeException or corrupt state
// Now: immediate, meaningful exception
cdt.InsertVertices([...]); // throws TriangulationFinalizedException
cdt.InsertEdges([...]);    // throws TriangulationFinalizedException
cdt.EraseSuperTriangle();  // throws TriangulationFinalizedException

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[github-actions]

Summary

Summary

Generated on:	2/24/2026 - 10:39:11 AM
Coverage date:	2/24/2026 - 10:39:08 AM
Parser:	Cobertura
Assemblies:	1
Classes:	18
Files:	7
Line coverage:	85.1% (1333 of 1566)
Covered lines:	1333
Uncovered lines:	233
Coverable lines:	1566
Total lines:	3877
Branch coverage:	79.6% (640 of 804)
Covered branches:	640
Total branches:	804
Method coverage:	Feature is only available for sponsors
Tag:	98_22345529175

Coverage

CDT.Core - 85.1%

Name	Line	Branch
CDT.Core	85.1%	79.6%
CDT.Box2d`1	73.6%	100%
CDT.CdtUtils	83.1%	72.8%
CDT.CovariantReadOnlyDictionary`3	18.1%	50%
CDT.DictionaryExtensions	100%	100%
CDT.DuplicatesInfo	100%
CDT.DuplicateVertexException	66.6%
CDT.Edge	75%	66.6%
CDT.IntersectingConstraintsException	0%
CDT.KdTree`1	72.7%	65%
CDT.LayerDepth	0%
CDT.Predicates.PredicatesAdaptive	92.6%	83.3%
CDT.Predicates.PredicatesExact	35.3%	100%
CDT.TopologyVerifier	77.2%	63.8%
CDT.Triangle	66.6%	71.4%
CDT.Triangulation`1	93.8%	84.8%
CDT.TriangulationException	100%
CDT.TriangulationFinalizedException	100%
CDT.V2d`1	44.4%	25%