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/observability.md

@@ -0,0 +1,14 @@
+# Observability
+
+## Telemetry signals
+- Metrics for scan latency, cache hit rate, policy evaluation time, queue depth.
+- Logs are structured and include correlation IDs.
+- Traces connect Scanner, Policy, Scheduler, and Notify workflows.
+
+## Audit trails
+- Signing and policy actions are recorded for compliance.
+- Tenant and actor metadata is included in audit records.
+
+## Telemetry stack
+- Telemetry module provides collectors, dashboards, and alert rules.
+- Offline bundles include telemetry assets for air-gapped installs.