refactor: 移除 IoT 卡未使用的价格字段

- 移除 IotCard 模型的 cost_price 和 distribute_price 字段
- 移除 StandaloneIotCardResponse DTO 中对应的字段
- 添加数据库迁移文件 000066_remove_iot_card_price_fields
- 更新 opencode.json 配置

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

internal/store/postgres/iot_card_store.go

@@ -211,12 +211,11 @@ func (s *IotCardStore) List(ctx context.Context, opts *store.QueryOptions, filte
 // standaloneListColumns 列表查询只选取响应需要的列，避免 SELECT * 的宽行 I/O
 var standaloneListColumns = []string{
 	"id", "iccid", "card_category", "carrier_id", "carrier_type", "carrier_name",
-	"imsi", "msisdn", "batch_no", "supplier", "cost_price", "distribute_price",
-	"status", "shop_id", "activated_at", "activation_status", "real_name_status",
-	"network_status", "data_usage_mb", "current_month_usage_mb", "current_month_start_date",
-	"last_month_total_mb", "last_data_check_at", "last_real_name_check_at",
-	"enable_polling", "series_id", "first_commission_paid", "accumulated_recharge",
-	"created_at", "updated_at",
+	"imsi", "msisdn", "batch_no", "supplier", "status", "shop_id", "activated_at",
+	"activation_status", "real_name_status", "network_status", "data_usage_mb",
+	"current_month_usage_mb", "current_month_start_date", "last_month_total_mb",
+	"last_data_check_at", "last_real_name_check_at", "enable_polling", "series_id",
+	"first_commission_paid", "accumulated_recharge", "created_at", "updated_at",
 }
 
 // ListStandalone 独立卡列表查询入口