Refactor quantity input parsing to handle additional units and improve conversion logic across inventory forms and recipe pages

frontend/app/api/products/route.ts

@@ -8,12 +8,7 @@ export async function GET(request: NextRequest) {
     cache: 'no-store',
   });
 
-  const text = await res.text();
+  const data = await res.json();
 
-  return new NextResponse(text, {
-    status: res.status,
-    headers: {
-      'Content-Type': 'application/json',
-    },
-  });
+  return NextResponse.json(data, { status: res.status });
 }