Clear design state after submission for approval

After a design is successfully submitted for approval, clear the
elementsFront and elementsBack state so users start with a blank
canvas when creating their next design.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/components/DesignCanvas.tsx

@@ -962,6 +962,9 @@ export default function DesignCanvas({ product, isAdminEditing = false }: { prod
           setDesignApprovalId(design.id);
           setApprovalStatus('PENDING');
           setSubmissionMessage(`✓ Design submitted for approval! You'll receive an email when it's ready to add to your bag.`);
+          // Clear design elements so user can start fresh
+          setElementsFront([]);
+          setElementsBack([]);
           // Save to localStorage so status persists on page reload
           if (typeof window !== 'undefined') {
             localStorage.setItem(`designApproval_${product.id}`, JSON.stringify({