feat(crypto): Complete Phase 2 - Configuration-driven crypto architecture with 100% compliance

## Summary

This commit completes Phase 2 of the configuration-driven crypto architecture, achieving
100% crypto compliance by eliminating all hardcoded cryptographic implementations.

## Key Changes

### Phase 1: Plugin Loader Infrastructure
- **Plugin Discovery System**: Created StellaOps.Cryptography.PluginLoader with manifest-based loading
- **Configuration Model**: Added CryptoPluginConfiguration with regional profiles support
- **Dependency Injection**: Extended DI to support plugin-based crypto provider registration
- **Regional Configs**: Created appsettings.crypto.{international,russia,eu,china}.yaml
- **CI Workflow**: Added .gitea/workflows/crypto-compliance.yml for audit enforcement

### Phase 2: Code Refactoring
- **API Extension**: Added ICryptoProvider.CreateEphemeralVerifier for verification-only scenarios
- **Plugin Implementation**: Created OfflineVerificationCryptoProvider with ephemeral verifier support
  - Supports ES256/384/512, RS256/384/512, PS256/384/512
  - SubjectPublicKeyInfo (SPKI) public key format
- **100% Compliance**: Refactored DsseVerifier to remove all BouncyCastle cryptographic usage
- **Unit Tests**: Created OfflineVerificationProviderTests with 39 passing tests
- **Documentation**: Created comprehensive security guide at docs/security/offline-verification-crypto-provider.md
- **Audit Infrastructure**: Created scripts/audit-crypto-usage.ps1 for static analysis

### Testing Infrastructure (TestKit)
- **Determinism Gate**: Created DeterminismGate for reproducibility validation
- **Test Fixtures**: Added PostgresFixture and ValkeyFixture using Testcontainers
- **Traits System**: Implemented test lane attributes for parallel CI execution
- **JSON Assertions**: Added CanonicalJsonAssert for deterministic JSON comparisons
- **Test Lanes**: Created test-lanes.yml workflow for parallel test execution

### Documentation
- **Architecture**: Created CRYPTO_CONFIGURATION_DRIVEN_ARCHITECTURE.md master plan
- **Sprint Tracking**: Created SPRINT_1000_0007_0002_crypto_refactoring.md (COMPLETE)
- **API Documentation**: Updated docs2/cli/crypto-plugins.md and crypto.md
- **Testing Strategy**: Created testing strategy documents in docs/implplan/SPRINT_5100_0007_*

## Compliance & Testing

- ✅ Zero direct System.Security.Cryptography usage in production code
- ✅ All crypto operations go through ICryptoProvider abstraction
- ✅ 39/39 unit tests passing for OfflineVerificationCryptoProvider
- ✅ Build successful (AirGap, Crypto plugin, DI infrastructure)
- ✅ Audit script validates crypto boundaries

## Files Modified

**Core Crypto Infrastructure:**
- src/__Libraries/StellaOps.Cryptography/CryptoProvider.cs (API extension)
- src/__Libraries/StellaOps.Cryptography/CryptoSigningKey.cs (verification-only constructor)
- src/__Libraries/StellaOps.Cryptography/EcdsaSigner.cs (fixed ephemeral verifier)

**Plugin Implementation:**
- src/__Libraries/StellaOps.Cryptography.Plugin.OfflineVerification/ (new)
- src/__Libraries/StellaOps.Cryptography.PluginLoader/ (new)

**Production Code Refactoring:**
- src/AirGap/StellaOps.AirGap.Importer/Validation/DsseVerifier.cs (100% compliant)

**Tests:**
- src/__Libraries/__Tests/StellaOps.Cryptography.Plugin.OfflineVerification.Tests/ (new, 39 tests)
- src/__Libraries/__Tests/StellaOps.Cryptography.PluginLoader.Tests/ (new)

**Configuration:**
- etc/crypto-plugins-manifest.json (plugin registry)
- etc/appsettings.crypto.*.yaml (regional profiles)

**Documentation:**
- docs/security/offline-verification-crypto-provider.md (600+ lines)
- docs/implplan/CRYPTO_CONFIGURATION_DRIVEN_ARCHITECTURE.md (master plan)
- docs/implplan/SPRINT_1000_0007_0002_crypto_refactoring.md (Phase 2 complete)

## Next Steps

Phase 3: Docker & CI/CD Integration
- Create multi-stage Dockerfiles with all plugins
- Build regional Docker Compose files
- Implement runtime configuration selection
- Add deployment validation scripts

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

docs2/ui/sbom-graph-explorer.md

@@ -0,0 +1,47 @@
+# SBOM graph explorer
+
+Purpose
+- Traverse components, dependencies, and overlays with deterministic filters.
+- Exports must include the overlay and filter set that produced them.
+
+Views and overlays
+- Inventory vs usage overlays for declared vs runtime-observed packages.
+- Reachability overlay highlights components reachable from entrypoints.
+- Policy overlay shows allow, deny, review verdicts with policy version.
+- VEX overlay marks components covered by claims and contested states.
+
+Filters
+- Package facets: ecosystem, name, version, license, supplier.
+- Reachability facets: entrypoint, call depth, evidence source.
+- Risk facets: severity, EPSS bucket, KEV flag, exploitability score.
+- Time facets: last-seen and last-scan timestamps.
+- Results are sorted deterministically by PURL then version.
+
+Saved views and exports
+- Saved views capture query, overlays, columns, sort, tenant, and graph_cache_epoch.
+- Exported NDJSON includes view_id, filters, overlays, results, and SHA-256 manifest.
+- Restoring a view warns when cache epochs differ.
+
+Interactions
+- Graph canvas supports zoom, pan, and node expansion with a max node cap.
+- Table panel stays in sync with canvas selection.
+- Details drawer shows PURL, provenance, and incoming or outgoing edges.
+- Search accepts PURL, package name, or CVE.
+
+Accessibility
+- Keyboard navigation across canvas, filters, table, and drawer.
+- Screen reader labels include overlay state.
+- High-contrast and reduced-motion modes are supported.
+
+Air-gap and caching
+- Offline bundles supply graph_cache_epoch for deterministic overlays.
+- Client cache invalidates on tenant switch or overlay version change.
+
+AOC visibility
+- Regulated tenants show an AOC enforced badge.
+- Exports include aoc=true flag when applicable.
+
+Related references
+- docs/api/graph.md
+- modules/graph.md
+- ui/reachability-overlays.md