feat(inventory-go): store od_rating at ingest + schema column

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

go-services/inventory-go/process.go

@@ -136,6 +136,10 @@ func (s *Server) processItem(raw map[string]any) map[string]any {
 		"remaining_lifespan":       nilNeg(ivI(iv, "268", -1)),
 	}
 
+	if od, ok := computeOD(raw); ok {
+		items["od_rating"] = od
+	}
+
 	// combat (sentinel defaults), then base values merged.
 	wt := ivI(iv, "218103835", -1)
 	if wt > 100 {