feat(client): 库存卡片显示单价（进价）+ 成本按角色隐藏

- 手机库存卡副行追加进价（编号 · 规格 · ¥xxx），仅管理员可见
- 宽屏成本价/总价列、货值 KPI、商品抽屉成本行对非管理员隐藏（isAdminProvider）
- m-inventory 原型同步 + 移动 golden ×6 重录（管理员形态基准）

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

client/lib/widgets/product_editor_drawer.dart

@@ -11,6 +11,7 @@ import 'package:go_router/go_router.dart';
 import 'package:image_picker/image_picker.dart';
 import 'package:lucide_icons_flutter/lucide_icons.dart';
 
+import '../core/auth/auth_state.dart';
 import '../core/config/app_config.dart';
 import '../core/utils/dialog_util.dart';
 import '../core/responsive/responsive.dart';
@@ -356,10 +357,14 @@ class _ProductEditorDrawerState extends ConsumerState<_ProductEditorDrawer> {
         b('${_fmtQty(widget.qty!)} ${widget.unit ?? p.unit}'.trim())
       ));
     }
+    // 成本仅管理员可见（与库存列表/出库同口径）；p.purchasePrice 兜底也要一并门控
+    final isAdmin = ref.watch(isAdminProvider);
     final cost = widget.cost ?? p.purchasePrice;
-    if (cost != null && cost > 0) rows.add(('成本价（单瓶）', b(_fmtMoney(cost))));
-    if (widget.qty != null && cost != null && cost > 0) {
-      rows.add(('总成本价', b(_fmtMoney(widget.qty! * cost))));
+    if (isAdmin && cost != null && cost > 0) {
+      rows.add(('成本价（单瓶）', b(_fmtMoney(cost))));
+      if (widget.qty != null) {
+        rows.add(('总成本价', b(_fmtMoney(widget.qty! * cost))));
+      }
     }
     if ((widget.status ?? '').isNotEmpty) {
       rows.add((