[ADD] website_sale_aplicoop: Product blacklist feature for group orders

- Add excluded_product_ids field for explicit product exclusion
- Blacklist has absolute priority over all inclusion sources (product_ids, category_ids, supplier_ids)
- Update _get_products_for_group_order() with blacklist filter logic
- Rename 'Associations' section to 'Catálogo de Productos' with subsections:
  * Productos Incluidos (whitelist: suppliers, categories, direct products)
  * Productos Excluidos (blacklist: explicit exclusions)
- Add comprehensive test suite (TestProductBlacklist class with 7 tests)
- Add Spanish and Euskera translations
- Update available_products_count computation to include excluded_product_ids
- Version bump to 18.0.1.4.0

Use case: Bulk inclusion via categories/suppliers + fine-grained exclusion via blacklist
Example: Select a category with 100 products, exclude 5 unwanted → 95 available

website_sale_aplicoop/models/group_order.py

@@ -188,6 +188,14 @@ class GroupOrder(models.Model):
         tracking=True,
         help="Products in these categories will be available",
     )
+    excluded_product_ids = fields.Many2many(
+        "product.product",
+        "group_order_excluded_product_rel",
+        "order_id",
+        "product_id",
+        tracking=True,
+        help="Products explicitly excluded from this order (blacklist has absolute priority)",
+    )
 
     # === Estado ===
     state = fields.Selection(
@@ -233,7 +241,7 @@ class GroupOrder(models.Model):
         help="Total count of available products from all sources",
     )
 
-    @api.depends("product_ids", "category_ids", "supplier_ids")
+    @api.depends("product_ids", "category_ids", "supplier_ids", "excluded_product_ids")
     def _compute_available_products_count(self):
         """Count all available products from all sources."""
         for record in self:
@@ -387,6 +395,17 @@ class GroupOrder(models.Model):
             ).filtered("active")
             products |= supplier_products
 
+        # 4) Apply blacklist filter (absolute priority)
+        if order.excluded_product_ids:
+            excluded_count = len(products & order.excluded_product_ids)
+            products = products - order.excluded_product_ids
+            _logger.info(
+                "Group order %d: Excluded %d products from blacklist (total available: %d)",
+                order.id,
+                excluded_count,
+                len(products),
+            )
+
         return products
 
     def _get_products_paginated(self, order_id, page=1, per_page=20):