feat(client): 库存三态 UI——抽屉挂售 switch + 三态徽章/筛选/已售 KPI 卡

- 新组件 DsSwitch（原型 atoms .switch 对照，L1 已登记：38×22 pill，on=primary）
- 商品抽屉状态行：三态徽章后跟挂售 switch（在售⇄库存 即时生效，已售只读，
  readonly 禁用），桌面 drawer / 移动 sheet 同组件
- 列表状态列/卡片徽章三态化（在售绿/库存蓝/已售灰，icons BADGE_ICON 补两词）；
  状态筛选改「全部/在售/库存/已售」走服务端；预警缺货退出状态维度由数量染色承担
- KPI 第四卡「缺货预警」→「已售」（sold_count，点击筛选已售）
- 原型同步：atoms/index 登记 switch 与 b-库存/b-已售、inventory 两屏三态数据、
  抽屉状态行 switch；12 道 ds 闸 + L1 同源闸全过
- golden 重录 ×9（三态徽章 + 已售卡形态）

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

client/lib/models/inventory.dart

@@ -9,6 +9,9 @@ class Inventory {
   final int? productId;
   final int? stockInItemId;
   final double quantity;
+
+  /// 库存三态（2026-07-07）：stock=库存 / on_sale=在售(公开酒单) / sold=已售(卖光留痕)
+  final String status;
   final String productCode;
   final String productName;
   final String series;
@@ -31,6 +34,7 @@ class Inventory {
     this.productId,
     this.stockInItemId,
     required this.quantity,
+    this.status = 'stock',
     this.productCode = '',
     this.productName = '',
     this.series = '',
@@ -54,6 +58,7 @@ class Inventory {
         productId: (json['product_id'] as num?)?.toInt(),
         stockInItemId: (json['stock_in_item_id'] as num?)?.toInt(),
         quantity: (json['quantity'] as num).toDouble(),
+        status: json['status'] as String? ?? 'stock',
         productCode: json['product_code'] as String? ?? '',
         productName: json['product_name'] as String? ?? '',
         series: json['series'] as String? ?? '',
@@ -77,6 +82,7 @@ class InventorySummary {
   final int skuCount;
   final double stockValue;
   final double inStockQty;
+  final int soldCount; // 已售留痕行数（status=sold）
   final int shortageCount;
   final int warningCount;
   // 月初快照（KPI 环比）：由 inventory_logs 反推
@@ -87,6 +93,7 @@ class InventorySummary {
     this.skuCount = 0,
     this.stockValue = 0,
     this.inStockQty = 0,
+    this.soldCount = 0,
     this.shortageCount = 0,
     this.warningCount = 0,
     this.lastMonthSku = 0,
@@ -97,6 +104,7 @@ class InventorySummary {
         skuCount: (j['sku_count'] as num?)?.toInt() ?? 0,
         stockValue: (j['stock_value'] as num?)?.toDouble() ?? 0,
         inStockQty: (j['in_stock_qty'] as num?)?.toDouble() ?? 0,
+        soldCount: (j['sold_count'] as num?)?.toInt() ?? 0,
         shortageCount: (j['shortage_count'] as num?)?.toInt() ?? 0,
         warningCount: (j['warning_count'] as num?)?.toInt() ?? 0,
         lastMonthSku: (j['last_month_sku'] as num?)?.toInt() ?? 0,