feat: UI 系统中心化 + 趋势图重构 + 法律文档 H5 上线

- UI 系统: 新增 design_tokens / module_visuals / app_buttons / app_status_badge / app_toast / ai_content 六个共享模块; 28 个页面接入, SnackBar 全部替换为 AppToast
- 趋势图: 直线折线 + 渐变填充 + 阴影; 去网格线; X 轴日+月份分隔; Y 轴整数刻度最多 4 个; 点击数据点/录入记录显示上方浮层, 选中点变实心
- 法律文档 H5: 后端 wwwroot 托管隐私政策/服务协议/关于/个人信息收集清单/第三方 SDK 清单 + 索引页; Program.cs 启用 UseDefaultFiles + UseStaticFiles
- 其他: auth_provider 登录流程调整; api_client IP 适配; 主页智能体栏间距优化

health_app/test/api_client_test.dart

@@ -0,0 +1,19 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:health_app/core/api_client.dart';
+
+void main() {
+  test('AuthExpiredNotifier notifies all current listeners once', () {
+    final notifier = AuthExpiredNotifier();
+    var first = 0;
+    var second = 0;
+
+    final removeFirst = notifier.addListener(() => first++);
+    notifier.addListener(() => second++);
+    notifier.notify();
+    removeFirst();
+    notifier.notify();
+
+    expect(first, 1);
+    expect(second, 2);
+  });
+}

health_app/test/app_router_test.dart

@@ -0,0 +1,27 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:health_app/core/app_router.dart';
+import 'package:health_app/core/navigation_provider.dart';
+
+void main() {
+  testWidgets(
+    'detail routes show an error instead of throwing when id is missing',
+    (tester) async {
+      await tester.pumpWidget(
+        ProviderScope(
+          child: Consumer(
+            builder: (context, ref, _) {
+              return MaterialApp(
+                home: buildPage(const RouteInfo('aiAnalysis'), ref),
+              );
+            },
+          ),
+        ),
+      );
+
+      expect(tester.takeException(), isNull);
+      expect(find.text('页面参数错误'), findsOneWidget);
+    },
+  );
+}

health_app/test/report_polling_test.dart

@@ -0,0 +1,11 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:health_app/pages/report/report_pages.dart';
+
+void main() {
+  test('report polling backs off and stops after the retry budget', () {
+    expect(reportAnalysisPollDelay(1), const Duration(seconds: 4));
+    expect(reportAnalysisPollDelay(3), const Duration(seconds: 8));
+    expect(reportAnalysisPollDelay(6), const Duration(seconds: 12));
+    expect(reportAnalysisPollDelay(16), isNull);
+  });
+}