refactor: calculate_product_cost 去掉客户级折扣，只算原价

折扣移到产品层按 product_id 精确计算（产品级折扣）。资源层不碰折扣。

storage_resource/product_interface.py

@@ -147,17 +147,8 @@ async def calculate_product_cost(resource_ref_id, usage_data, user_org_id=None):
 
     amount = sum(getattr(p, 'amount', 0) for p in prices)
 
-    # 客户折扣：资源真实定价 × 客户折扣 = 成交价（照 llmage 范式）
-    discount = 1.0
-    if user_org_id:
-        try:
-            d = await env.get_customer_discount(
-                getattr(spec, 'org_id', '') or '0', user_org_id)
-            if d not in (None, '', 0):
-                discount = float(d)
-        except Exception:
-            discount = 1.0
-
-    return {'success': True, 'amount': round(amount * discount, 6),
+    # 资源层只算真实定价（原价）。产品级折扣（客户/分销商/供应商）由产品层
+    # calculate_product_cost 按 product_id 精确计算，见 product_management.core。
+    return {'success': True, 'amount': round(amount, 6),
             'original_amount': round(amount, 6),
-            'cost': 0.0, 'discount': discount, 'pricing_program_id': ppid}
+            'cost': 0.0, 'discount': 1.0, 'pricing_program_id': ppid}