Fully separated payment quotation and orchestration flows

api/payments/orchestrator/internal/service/shared/idempotency.go

@@ -0,0 +1,17 @@
+package shared
+
+import (
+	"fmt"
+	"strings"
+)
+
+func PerIntentIdempotencyKey(base string, index int, total int) string {
+	base = strings.TrimSpace(base)
+	if base == "" {
+		return ""
+	}
+	if total <= 1 {
+		return base
+	}
+	return fmt.Sprintf("%s:%d", base, index+1)
+}