feat: DEBT-014 + DEBT-029 Audit Infrastructure (Duplicate Detection & Event Logging)

DEBT-014: Duplicate detection & reconciliation tracking
- Create operation_audit_trail migration (0011)
- Hook OutboxPollerJob to detect and log duplicates
- Implement MetricsSql queries for duplicate/reconciliation metrics

DEBT-029: Audit trail consumer integration
- Create AuditTrailConsumer for event-driven audit logging
- Map 12+ event types to compliance.operation_audit_trail
- Register consumer in Program.cs DI and OutboxPollerJob

AGENTS.md v16.0 Compliance:
✅ Necessity: Both DEBT items from registry (2+3 pts)
✅ Simplicity: Event-driven via Outbox pattern (existing infra)
✅ Pattern: Vertical Slice consumer + SQL queries (established)
✅ Traceability: All event types documented and mapped
✅ Safety: Idempotent logging via ON CONFLICT DO NOTHING
✅ Maturity: Framework ready before feature implementation

Impact: Medium/High (5 pts total, Q3 target 4 pts exceeded)
Status: Code ready, awaiting SSH tunnel for migration test

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

src/KArtSell.Host/Program.cs

@@ -96,6 +96,7 @@ builder.Services.AddScoped<KArtSell.Host.Features.ShadowRun.GetShadowRunQuery>()
 builder.Services.AddScoped<KArtSell.Host.Consumers.ShadowRunCompletedConsumer>();
 builder.Services.AddScoped<KArtSell.Host.Consumers.ApprovalQueueConsumer>();
 builder.Services.AddScoped<KArtSell.Host.Consumers.AuditLogConsumer>();
+builder.Services.AddScoped<KArtSell.Host.Consumers.AuditTrailConsumer>();
 
 // Recommendation Report Services
 builder.Services.AddScoped<RecommendationReportGenerator>();