[IMP] website_sale_aplicoop: propagate consumer_group_id directly from group_order

- Add consumer_group_id to sale.order for tracking the consumer group
- Fix stock.picking consumer_group_id to use sale_id.consumer_group_id
- Add group_ids inverse relation in res.partner for bidirectional access
- Remove auto-calculation of consumer_group_id, data comes directly from group_order.group_ids[0]
- Add debug logging for consumer_group propagation
- commitment_date propagates directly from group_order (no recalculation)

website_sale_aplicoop/models/stock_picking_extension.py

@@ -35,10 +35,10 @@ class StockPicking(models.Model):
 
     consumer_group_id = fields.Many2one(
         "res.partner",
-        related="sale_id.partner_id",
+        related="sale_id.consumer_group_id",
         string="Consumer Group",
         store=True,
         readonly=True,
         domain=[("is_group", "=", True)],
-        help="Consumer group (partner) from sale order for warehouse grouping",
+        help="Consumer group (res.partner with is_group=True) from sale order",
     )