feat(server): auth indexes + default-org backfill migration

server/cmd/main.go

@@ -24,6 +24,13 @@ func main() {
 	}
 	log.Println("connected to MongoDB")
 
+	if err := services.EnsureAuthIndexes(); err != nil {
+		log.Printf("warning: failed to ensure auth indexes: %v", err)
+	}
+	if err := services.RunMigrations(); err != nil {
+		log.Fatalf("migration failed: %v", err)
+	}
+
 	if err := services.EnsureSecretIndexes(); err != nil {
 		log.Printf("warning: failed to ensure secret indexes: %v", err)
 	}