feat(client): 草稿 KPI 卡（暗黄）+ 出库详情总售价列 + 明细去¥缩号 + 建单默认值 + 若干列名

- 出入库列表加草稿 KPI 卡（DsKpiTone.warn 新档，审核卡后，点击筛选草稿）
- 出库详情 7 列：售价后加总售价；明细行内价格去 ¥ 且缩一号（合计保留 ¥）；
  5/7 列宽重排（系列/数量左移、进价（单瓶）不折行）
- 出库建单：数量默认=可用数量、售价默认=参考售价（product.sale_price）
- 入库详情列名：进价（单瓶）/总价；库存列表「单价」→「总价」（库存×成本）；
  商品抽屉：成本价（单瓶）/总成本价
- 公开商品预览页加返回按钮（仅 App 内 canPop 时显示，扫码直达保持纯净）

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JJ1g8XV1YhhmHRzhwWEW7o

client/lib/models/stock_summary.dart

@@ -4,6 +4,7 @@ class StockSummary {
   final int monthCount;
   final double monthAmount;
   final int pendingCount;
+  final int draftCount;
   final int lastMonthCount;
   final double lastMonthAmount;
 
@@ -11,6 +12,7 @@ class StockSummary {
     this.monthCount = 0,
     this.monthAmount = 0,
     this.pendingCount = 0,
+    this.draftCount = 0,
     this.lastMonthCount = 0,
     this.lastMonthAmount = 0,
   });
@@ -19,6 +21,7 @@ class StockSummary {
         monthCount: (j['month_count'] as num?)?.toInt() ?? 0,
         monthAmount: (j['month_amount'] as num?)?.toDouble() ?? 0,
         pendingCount: (j['pending_count'] as num?)?.toInt() ?? 0,
+        draftCount: (j['draft_count'] as num?)?.toInt() ?? 0,
         lastMonthCount: (j['last_month_count'] as num?)?.toInt() ?? 0,
         lastMonthAmount: (j['last_month_amount'] as num?)?.toDouble() ?? 0,
       );