# Validation Harness and Reproducibility Verification

## Module
BinaryIndex

## Status
IMPLEMENTED

## Description
Validation harness with determinism validation, SBOM stability checking, and reproducible build verification. Includes local rebuild backend and bundle export/import.

## Implementation Details
- **Modules**: `src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Validation/`, `src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.GroundTruth.Reproducible/`, `src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Builders/`
- **Key Classes**:
  - `ValidationHarness` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.Validation/ValidationHarness.cs`) - main validation harness with `IMatcherAdapterFactory` for pluggable matching
  - `ValidationHarnessService` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.GroundTruth.Reproducible/ValidationHarnessService.cs`) - reproducible-build validation with `ValidationRunContext`
  - `ReproducibleBuildJob` (`src/BinaryIndex/StellaOps.BinaryIndex.Worker/Jobs/ReproducibleBuildJob.cs`) - local rebuild backend
  - `KpiRegressionService` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.GroundTruth.Reproducible/Services/KpiRegressionService.cs`) - SBOM stability and KPI regression tracking
- **Bundle Export/Import**: `ServiceCollectionExtensions.AddCorpusBundleExport/Import` (`src/BinaryIndex/__Libraries/StellaOps.BinaryIndex.GroundTruth.Reproducible/ServiceCollectionExtensions.cs`)
- **Interfaces**: `IValidationHarness`, `IKpiRegressionService`, `IReproducibleBuildJob`
- **Registration**: `ValidationServiceCollectionExtensions.AddValidationHarness()`

## E2E Test Plan
- [ ] Run validation harness and verify deterministic results for identical inputs
- [ ] Verify SBOM stability checking detects unstable hash generation
- [ ] Verify reproducible build verification: rebuild from source and compare against original binary
- [ ] Verify bundle export produces a self-contained archive importable on air-gapped systems
- [ ] Verify bundle import restores corpus data and enables offline validation
- [ ] Verify KPI regression tracking across multiple validation harness runs