feat(client): 网络恢复自动刷新 + 离线嗅探 + 连通性感知登录

网络嗅探与自动恢复：
- ConnectivityNotifier：在线时 30s 检测，离线时切换为 1min 嗅探
- 新增 networkRecoveryCountProvider：网络恢复时自增，各数据 provider
  通过 ref.watch 实现自动重新加载
- inventory/product/stock_in/stock_out/partner provider 均已接入

FutureBuilder 类屏幕：
- finance_screen + batch_tracking_screen 通过 ref.listen 监听恢复事件

修复问题 1：API 超时 10s/30s → 5s/15s，减少无网络时等待
修复问题 2：offline banner 文字由"写操作已禁用"改为实际行为描述

连通性感知：
- app 启动时（_AppBootstrap）立即 forceCheck，路由跳转前状态已就绪
- 登录页：watch connectivityProvider，离线时显示警告 banner
- 登录按钮：离线状态下直接提示，不等待超时

测试：
- login_screen_test + login_flow_test 通过 ConnectivityNotifier(skipInit: true)
  覆盖 provider，避免测试环境中 pending HTTP timer

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/test/login_screen_test.dart

@@ -2,7 +2,9 @@ import 'package:flutter/material.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:go_router/go_router.dart';
+import 'package:jiu_client/providers/connectivity_provider.dart';
 import 'package:jiu_client/screens/auth/login_screen.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 
 /// Wrap the screen in the minimum required providers.
 Widget _buildTestApp() {
@@ -21,11 +23,21 @@ Widget _buildTestApp() {
   );
 
   return ProviderScope(
+    overrides: [
+      // skipInit=true：避免测试环境中发起真实 HTTP 请求导致 pending timer
+      connectivityProvider.overrideWith(
+        (_) => ConnectivityNotifier(skipInit: true),
+      ),
+    ],
     child: MaterialApp.router(routerConfig: router),
   );
 }
 
 void main() {
+  setUp(() {
+    SharedPreferences.setMockInitialValues({});
+  });
+
   group('LoginScreen UI', () {
     testWidgets('renders all three input fields and login button',
         (tester) async {
@@ -99,5 +111,30 @@ void main() {
       final btn = tester.widget<ElevatedButton>(find.byType(ElevatedButton));
       expect(btn.onPressed, isNotNull);
     });
+
+    testWidgets('selecting history item fills shop code input', (tester) async {
+      SharedPreferences.setMockInitialValues({
+        'login_history_hotels': ['S001', 'H001'],
+      });
+
+      tester.view.physicalSize = const Size(1280, 800);
+      tester.view.devicePixelRatio = 1.0;
+      addTearDown(tester.view.resetPhysicalSize);
+
+      await tester.pumpWidget(_buildTestApp());
+      await tester.pumpAndSettle();
+
+      await tester.tap(find.widgetWithText(TextFormField, '请输入门店编号'));
+      await tester.pumpAndSettle();
+
+      expect(find.text('S001'), findsOneWidget);
+      await tester.tap(find.text('S001').last);
+      await tester.pumpAndSettle();
+
+      final field = tester.widget<TextFormField>(
+        find.byType(TextFormField).first,
+      );
+      expect(field.controller!.text, 'S001');
+    });
   });
 }