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>

src/Scanner/StellaOps.Scanner.WebService/Program.cs

@@ -804,6 +804,7 @@ apiGroup.MapProofBundleEndpoints();
 apiGroup.MapUnknownsEndpoints();
 apiGroup.MapSecretDetectionSettingsEndpoints(); // Sprint: SPRINT_20260104_006_BE
 apiGroup.MapSecurityAdapterEndpoints(); // Pack v2 security adapter routes
+apiGroup.MapScanPolicyEndpoints(); // Sprint: S1-T03 Scan Policy CRUD
 
 if (resolvedOptions.Features.EnablePolicyPreview)
 {