feat(scanner): Complete PoE implementation with Windows compatibility fix

- Fix namespace conflicts (Subgraph → PoESubgraph)
- Add hash sanitization for Windows filesystem (colon → underscore)
- Update all test mocks to use It.IsAny<>()
- Add direct orchestrator unit tests
- All 8 PoE tests now passing (100% success rate)
- Complete SPRINT_3500_0001_0001 documentation

Fixes compilation errors and Windows filesystem compatibility issues.
Tests: 8/8 passing
Files: 8 modified, 1 new test, 1 completion report

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

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

docs2/testing-and-quality.md

@@ -0,0 +1,19 @@
+# Testing and quality
+
+## Principles
+- Determinism is a contract: identical inputs must yield identical outputs.
+- Offline-first: tests should pass without network access.
+- Evidence-first: assertions cover evidence chains, not only verdicts.
+
+## Test layers
+- Unit and property tests for core libraries.
+- Integration tests with PostgreSQL and Valkey.
+- Contract tests for OpenAPI and schemas.
+- End-to-end tests for scan, policy, and offline workflows.
+- Replay verification against golden corpora.
+
+## Quality gates
+- Determinism checks on replay outputs.
+- Interop checks against external tooling formats.
+- Offline E2E runs as a release gate.
+- Policy and schema validation in CI.