fix: add price input to manual register

lib/ui/add_page/widgets/form_popup.dart

@@ -166,6 +166,7 @@ class _FullyManualState extends State<_FullyManual> {
   String? ean = "";
   String? title;
   String? author;
+  num? price;
 
   @override
   Widget build(BuildContext context) {
@@ -227,6 +228,26 @@ class _FullyManualState extends State<_FullyManual> {
                 author = newValue;
               },
             ),
+            SizedBox(height: 10),
+            TextFormField(
+              decoration: InputDecoration(
+                labelText: "Prix",
+                border: OutlineInputBorder(),
+                suffixText: "€",
+              ),
+              keyboardType: TextInputType.number,
+              validator: (value) {
+                if (value == null || value.isEmpty) {
+                  return "Indiquez un prix";
+                } else if (num.tryParse(value) == null) {
+                  return "Le prix doit être un nombre";
+                }
+                return null;
+              },
+              onSaved: (newValue) {
+                price = num.parse(newValue!);
+              },
+            ),
           ],
         ),
       ),