fix(inventory-go): backfill-od clears stale od_rating for non-matching weapons

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

go-services/inventory-go/ingest.go

@@ -259,10 +259,10 @@ func (s *Server) handleBackfillOD(w http.ResponseWriter, r *http.Request) {
 	}
 	type upd struct {
 		id int
-		od float64
+		od *float64 // nil → clear stale OD (weapon no longer matches any rule)
 	}
 	var updates []upd
-	scanned := 0
+	scanned, rated := 0, 0
 	for rows.Next() {
 		var id int
 		var oj map[string]any
@@ -273,7 +273,13 @@ func (s *Server) handleBackfillOD(w http.ResponseWriter, r *http.Request) {
 		}
 		scanned++
 		if od, ok := computeOD(oj); ok {
-			updates = append(updates, upd{id, od})
+			v := od
+			updates = append(updates, upd{id, &v})
+			rated++
+		} else {
+			// No matching rule → ensure od_rating is NULL (clears any stale value
+			// from a prior formula so the column never keeps a wrong number).
+			updates = append(updates, upd{id, nil})
 		}
 	}
 	rows.Close()
@@ -285,7 +291,7 @@ func (s *Server) handleBackfillOD(w http.ResponseWriter, r *http.Request) {
 		}
 		updated++
 	}
-	writeJSON(w, http.StatusOK, map[string]any{"scanned": scanned, "updated": updated})
+	writeJSON(w, http.StatusOK, map[string]any{"scanned": scanned, "rated": rated, "updated": updated})
 }
 
 func parseNaiveTime(s string) time.Time {