Add scan policy CRUD system (Sprint 002 S1-T03)

Backend (Scanner .NET):
- New ScanPolicyEndpoints.cs with GET/POST/PUT/DELETE /api/v1/scan-policies
- In-memory ConcurrentDictionary storage (no migration needed)
- Auth: scanner:read for list, orch:operate for mutations
- Registered in Scanner Program.cs

Frontend (Angular):
- New scan-policy.component.ts with table view, inline create/edit form,
  enable/disable toggle, dynamic rules (type/severity/action)
- Route added at /security/scan-policies in security-risk.routes.ts

Gateway route already exists in router-gateway-local.json.
Sprint 002: all 7 tasks now DONE.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/implplan/SPRINT_20260316_002_Scanner_entry_point_and_vulnerability_navigation.md

@@ -28,7 +28,7 @@ Dependency: S1-T01
 Owners: Developer
 
 ### S1-T03 - Full scan policy system
-Status: TODO
+Status: DONE
 Dependency: S1-T02
 Owners: Developer