[FIX] website_sale_aplicoop: Calculate UoM quantity step server-side for portal users

Portal users cannot read uom.uom model due to ACL restrictions (1,0,0,0 permissions).
This caused products sold by weight (kg) to have incorrect quantity step (1 instead of 0.1).

Solution:
- Calculate quantity_step in Python controller using product.uom_id.sudo()
- Check if UoM category contains 'weight' or 'kg' -> use step=0.1
- For other products, use default step=1
- Pass quantity_step to template via product_display_info dict
- Update XML input attributes (value, min, step) to use dynamic quantity_step

This maintains proper UX for bulk products while respecting security permissions.

website_sale_aplicoop/views/website_templates.xml

@@ -1225,6 +1225,10 @@
                             t-set="safe_uom_category"
                             t-value="product_display_info.get(product.id, {}).get('safe_uom_category', '')"
                         />
+                    <t
+                            t-set="quantity_step"
+                            t-value="product_display_info.get(product.id, {}).get('quantity_step', 1)"
+                        />
                     <t
                             t-set="order_id_safe"
                             t-value="group_order.id if group_order else ''"
@@ -1236,6 +1240,7 @@
                             t-attf-data-product-name="{{ product.name }}"
                             t-attf-data-product-price="{{ display_price }}"
                             t-attf-data-uom-category="{{ safe_uom_category }}"
+                            t-attf-data-quantity-step="{{ quantity_step }}"
                         >
                         <div class="qty-control">
                             <label
@@ -1259,9 +1264,9 @@
                                     t-attf-id="qty_{{ product.id }}"
                                     class="product-qty"
                                     name="quantity"
-                                    value="1"
-                                    min="1"
-                                    step="1"
+                                    t-attf-value="1"
+                                    t-attf-min="{{ quantity_step }}"
+                                    t-attf-step="{{ quantity_step }}"
                                 />
                             <button
                                     class="qty-increase"