7-3 成本单价改为产品定价模板单价(base_unit_price)并显示单位

- 后端enrich_items_from_db返回base_unit_price和pricing_unit
- formula_detail支持面积/重量/件等多种定价类型
- 前端成本单价列显示如¥150/㎡而非一件总价¥6000

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/services/order_service.py

@@ -308,15 +308,24 @@ class OrderService:
                 rule = rules_map[item.product_id]
                 item_dict["formula_expr"] = getattr(rule, "formula_expr", None)
                 item_dict["formula_note"] = getattr(rule, "formula_note", None)
+                item_dict["base_unit_price"] = float(rule.base_unit_price or 0)
+                item_dict["pricing_unit"] = getattr(rule, "pricing_unit", None)
                 # 构建人类可读的计算过程
                 if not item_dict.get("formula_detail"):
                     try:
+                        unit_price = float(rule.base_unit_price or 0)
+                        pricing_type = getattr(rule, "pricing_type", "area") or "area"
+                        pricing_unit = getattr(rule, "pricing_unit", "㎡") or "㎡"
+                        qty = float(item.quantity or 0)
                         length = float(getattr(item, "length_m", 0) or 0)
                         width = float(getattr(item, "width_m", 0) or 0)
-                        unit_price = float(rule.base_unit_price or 0)
+                        if pricing_type == "area" and length and width and unit_price:
-                        if length and width and unit_price:
                             area = length * width
-                            item_dict["formula_detail"] = f"{length}m × {width}m × ¥{unit_price}/㎡ = ¥{area * unit_price:.2f}"
+                            item_dict["formula_detail"] = f"{length}m × {width}m × ¥{unit_price}/{pricing_unit} = ¥{area * unit_price:.2f}"
+                        elif pricing_type in ("kg", "weight_g") and qty and unit_price:
+                            item_dict["formula_detail"] = f"{qty}{pricing_unit} × ¥{unit_price}/{pricing_unit} = ¥{qty * unit_price:.2f}"
+                        elif unit_price:
+                            item_dict["formula_detail"] = f"{qty}{pricing_unit} × ¥{unit_price}/{pricing_unit} = ¥{qty * unit_price:.2f}"
                     except Exception:
                         pass
 

frontend/web-admin/src/views/OrdersPage.vue

@@ -334,7 +334,7 @@
                     <td>{{ item.demand_specification || "-" }}</td>
                     <td>{{ item.unit || '-' }}</td>
                     <td>{{ computeTotalDemand(item) || item.quantity }}</td>
-                    <td>¥{{ Number(item.cost_price || 0).toFixed(2) }}</td>
+                    <td>¥{{ Number(item.base_unit_price || item.cost_price || 0).toFixed(2) }}{{ item.pricing_unit ? '/' + item.pricing_unit : '' }}</td>
                     <td style="font-size:12px;color:#666;white-space:nowrap;">
                       {{ item.formula_detail || `${item.quantity} × ¥${Number(item.cost_price || 0).toFixed(2)}` }}
                     </td>