feat(client): 商品详情升级富数据版（KPI + 仓库分布 + 流水）

接后端新能力：listInventory 加 productId 透传；详情异步拉本商品库存+流水（失败
静默不阻塞主数据），渲染原型富数据三件套：
- 3 KPI 卡（当前库存 / 库存货值=库存×进价 / 近30天出库=出库流水30天聚合）
- 各仓库库存分布（按仓库分组 数量+货值）
- 近期流水（StatusPill 入/出 + 增减量，最近 8 条）
价格历史待后端第二步。整屏 golden ×三主题入回归闸。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TSKEiHsvauyxYUW2itzUXX

client/test/golden/product_detail_golden_test.dart

@@ -0,0 +1,92 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:shared_preferences/shared_preferences.dart';
+import 'package:jiu_client/core/models/page_result.dart';
+import 'package:jiu_client/models/product.dart';
+import 'package:jiu_client/models/inventory.dart';
+import 'package:jiu_client/providers/product_provider.dart';
+import 'package:jiu_client/providers/inventory_provider.dart';
+import 'package:jiu_client/repositories/product_repository.dart';
+import 'package:jiu_client/repositories/inventory_repository.dart';
+import 'package:jiu_client/screens/products/product_detail_screen.dart';
+
+import '../support/golden_harness.dart';
+
+/// design-distill 阶段4：商品详情「富数据版」golden × 三主题。
+/// 验证 3 KPI（当前库存/货值/近30天出库）+ 各仓库分布 + 近期流水（接后端
+/// /inventory?product_id + /inventory/logs?product_id 聚合）。
+/// 更新基准：flutter test --update-goldens test/golden/product_detail_golden_test.dart
+
+class _FakeProductRepo implements ProductRepository {
+  @override
+  Future<Product> getDetail(int id) async => const Product(
+        id: 1, code: 'MT-FT-500', name: '茅台 飞天 53°', unit: '件',
+        series: '飞天', spec: '500ml×6', brand: '茅台',
+        purchasePrice: 2680, categoryName: '酱香');
+  @override
+  dynamic noSuchMethod(Invocation invocation) =>
+      super.noSuchMethod(invocation);
+}
+
+class _FakeInvRepo implements InventoryRepository {
+  @override
+  Future<PageResult<Inventory>> listInventory({
+    int? warehouseId,
+    int? productId,
+    String? keyword,
+    List<String>? series,
+    List<String>? spec,
+    int page = 1,
+    int pageSize = 50,
+  }) async =>
+      const PageResult(data: [
+        Inventory(id: 1, productId: 1, quantity: 92, warehouseName: '主仓'),
+        Inventory(id: 2, productId: 1, quantity: 28, warehouseName: '二号仓'),
+        Inventory(id: 3, productId: 1, quantity: 8, warehouseName: '冷藏库'),
+      ], total: 3, page: 1, pageSize: 1000);
+
+  @override
+  Future<PageResult<InventoryLog>> listLogs({
+    int? warehouseId,
+    int? productId,
+    int page = 1,
+    int pageSize = 50,
+  }) async =>
+      const PageResult(data: [
+        InventoryLog(
+            warehouseId: 1, productId: 1, direction: 'in', quantity: 24,
+            createdAt: '2026-06-20T09:00:00'),
+        InventoryLog(
+            warehouseId: 1, productId: 1, direction: 'out', quantity: 12,
+            createdAt: '2026-06-18T09:00:00'),
+        InventoryLog(
+            warehouseId: 2, productId: 1, direction: 'out', quantity: 18,
+            createdAt: '2026-06-15T09:00:00'),
+        InventoryLog(
+            warehouseId: 1, productId: 1, direction: 'in', quantity: 36,
+            createdAt: '2026-06-12T09:00:00'),
+      ], total: 4, page: 1, pageSize: 100);
+
+  @override
+  dynamic noSuchMethod(Invocation invocation) =>
+      super.noSuchMethod(invocation);
+}
+
+List<Override> _overrides() => [
+      productRepositoryProvider.overrideWithValue(_FakeProductRepo()),
+      inventoryRepositoryProvider.overrideWithValue(_FakeInvRepo()),
+    ];
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+  SharedPreferences.setMockInitialValues({});
+
+  goldenAcrossThemes(
+    'product detail 富数据(桌面)',
+    goldenPrefix: 'product_detail',
+    child: () => const Scaffold(body: ProductDetailScreen(productId: 1)),
+    overrides: _overrides,
+    logical: const Size(1100, 1300),
+  );
+}

client/test/stock_out_insufficient_stock_flow_test.dart

@@ -94,6 +94,7 @@ class _FakeInventoryRepository extends InventoryRepository {
   @override
   Future<PageResult<Inventory>> listInventory({
     int? warehouseId,
+    int? productId,
     String? keyword,
     List<String>? series,
     List<String>? spec,