feat: validate local G2 candidate quality

ClumsyPilot/tests/verify_path_smoothing_local_g2_candidates.ps1

@@ -74,4 +74,43 @@ $gearBoundary = Invoke-Scenario 'GearBoundary'
 Assert-True $gearBoundary.GearBoundaryMarkerPreserved `
     'A window touching a gear-switch segment boundary must preserve its point-level gear marker.'
 
+$evaluatorType = Get-RequiredType 'MultiWheelC.TrajectoryPlanning.PathSmoothing.LocalG2.LocalG2CandidateEvaluator'
+$evaluatorHooksType = $evaluatorType.GetNestedType('TestHooks', [Reflection.BindingFlags]'Public,NonPublic')
+Assert-True ($null -ne $evaluatorHooksType) 'LocalG2CandidateEvaluator must expose narrowly scoped deterministic TestHooks.'
+$evaluateMethod = $evaluatorHooksType.GetMethod('Execute', [Reflection.BindingFlags]'Public,Static')
+Assert-True ($null -ne $evaluateMethod) 'TestHooks must execute deterministic candidate quality-gate scenarios.'
+
+function Invoke-EvaluationScenario([string]$Scenario) {
+    return $evaluateMethod.Invoke($null, @($Scenario))
+}
+
+$tooFar = Invoke-EvaluationScenario 'TooFar'
+Assert-Equal 'DeviationExceeded' $tooFar.FailureReason `
+    'A collision-free candidate more than 0.10 m from the raw window must be rejected.'
+
+$overshoot = Invoke-EvaluationScenario 'Overshoot'
+Assert-Equal 'CurvatureOvershoot' $overshoot.FailureReason `
+    'A candidate outside the raw regional curvature range must be rejected.'
+
+$noOp = Invoke-EvaluationScenario 'NoOp'
+Assert-Equal 'InsufficientImprovement' $noOp.FailureReason `
+    'A safe no-op must not be accepted.'
+
+$oscillating = Invoke-EvaluationScenario 'Oscillating'
+Assert-Equal 'VariationCostRegression' $oscillating.FailureReason `
+    'Repeated curvature oscillation must fail the variation-cost gate.'
+
+$lowClearance = Invoke-EvaluationScenario 'LowClearance'
+Assert-Equal 'InsufficientClearance' $lowClearance.FailureReason `
+    'A path with less than 0.02 m checked clearance must be rejected.'
+
+$improved = Invoke-EvaluationScenario 'Improved'
+Assert-Equal 'Accepted' $improved.Status `
+    'A safe candidate with at least 20 percent peak improvement must be accepted.'
+
+$smallestDeviation = Invoke-EvaluationScenario 'SmallestDeviation'
+$best = Invoke-EvaluationScenario 'Best'
+Assert-Equal $smallestDeviation.CandidateIndex $best.CandidateIndex `
+    'Among sufficient candidates, minimum deviation must win before extra smoothness.'
+
 Write-Output 'Path smoothing Local G2 candidate checks passed.'