perf: Fix N+1 query in production line dashboard (27s → <1s)

GetLineDashboard called GetLatestAssessment per hazard (N+1 queries).
Replaced with GetLatestAssessmentsByProject — one batch query per
station instead of one per hazard. With 50+ hazards across multiple
stations, this reduces hundreds of DB queries to ~5.

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

ai-compliance-sdk/internal/iace/store_production_lines.go

@@ -256,10 +256,12 @@ func (s *Store) buildStationDashboard(ctx context.Context, st ProductionLineStat
 	mitigations, _ := s.ListMitigationsByProject(ctx, st.ProjectID)
 	sd.MitigationCount = len(mitigations)
 
-	// Compute risk summary and max SIL/PL from latest assessments
+	// Batch-load all latest assessments in ONE query (not N+1)
+	latestByHazard, _ := s.GetLatestAssessmentsByProject(ctx, st.ProjectID)
+
 	for _, h := range hazards {
-		latest, _ := s.GetLatestAssessment(ctx, h.ID)
+		latest, ok := latestByHazard[h.ID]
-		if latest == nil {
+		if !ok {
 			continue
 		}