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/lib/pages/device/device_scan_page.dart

@@ -14,6 +14,7 @@ import '../../models/bp_reading.dart';
 import '../../providers/auth_provider.dart';
 import '../../providers/omron_device_provider.dart';
 import '../../services/health_ble_service.dart';
+import '../../widgets/app_toast.dart';
 import '../../widgets/ble_sync_dialog.dart';
 
 class DeviceScanPage extends ConsumerStatefulWidget {
@@ -71,16 +72,18 @@ class _DeviceScanPageState extends ConsumerState<DeviceScanPage>
       _results.clear();
     });
 
-    await [Permission.bluetoothScan, Permission.bluetoothConnect].request();
+    if (!await _ensureBlePermissions()) {
+      if (mounted) setState(() => _scanning = false);
+      return;
+    }
 
     if (Platform.isAndroid) {
       final locStatus = await Permission.locationWhenInUse.serviceStatus;
       if (locStatus != ServiceStatus.enabled && mounted) {
-        ScaffoldMessenger.of(context).showSnackBar(
-          const SnackBar(
-            content: Text('请先打开定位服务，否则可能无法发现蓝牙设备'),
-            backgroundColor: AppColors.warning,
-          ),
+        AppToast.show(
+          context,
+          '请先打开定位服务，否则可能无法发现蓝牙设备',
+          type: AppToastType.warning,
         );
       }
     }
@@ -183,16 +186,12 @@ class _DeviceScanPageState extends ConsumerState<DeviceScanPage>
         result.timeStamp.isBefore(scanStartedAt) ||
         !result.advertisementData.connectable ||
         DateTime.now().difference(result.timeStamp) > _visibleDeviceWindow) {
-      ScaffoldMessenger.of(
-        context,
-      ).showSnackBar(const SnackBar(content: Text('设备已离线，请重新进入通信状态')));
+      AppToast.show(context, '设备已离线，请重新进入通信状态', type: AppToastType.warning);
       return;
     }
     if (ref.read(omronDeviceProvider).isBound &&
         ref.read(omronDeviceProvider).findById(remoteId) != null) {
-      ScaffoldMessenger.of(
-        context,
-      ).showSnackBar(const SnackBar(content: Text('该设备已绑定')));
+      AppToast.show(context, '该设备已绑定', type: AppToastType.info);
       return;
     }
     setState(() => _connectingId = remoteId);
@@ -231,31 +230,24 @@ class _DeviceScanPageState extends ConsumerState<DeviceScanPage>
       if (mounted) popRoute(ref);
     } on TimeoutException {
       if (mounted && boundDevice != null) {
-        ScaffoldMessenger.of(context).showSnackBar(
-          SnackBar(content: Text('${boundDevice.type.label}已绑定，但本次未收到数据')),
+        AppToast.show(
+          context,
+          '${boundDevice.type.label}已绑定，但本次未收到数据',
+          type: AppToastType.warning,
         );
         popRoute(ref);
       } else if (mounted) {
-        ScaffoldMessenger.of(context).showSnackBar(
-          const SnackBar(
-            content: Text('连接超时，请确认设备仍处于通信状态'),
-            backgroundColor: AppColors.error,
-          ),
-        );
+        AppToast.show(context, '连接超时，请确认设备仍处于通信状态', type: AppToastType.error);
         unawaited(_startScan());
       }
     } on UnsupportedBleDeviceException catch (e) {
       if (mounted) {
-        ScaffoldMessenger.of(context).showSnackBar(
-          SnackBar(content: Text(e.message), backgroundColor: AppColors.error),
-        );
+        AppToast.show(context, e.message, type: AppToastType.error);
         unawaited(_startScan());
       }
     } catch (e) {
       if (mounted) {
-        ScaffoldMessenger.of(context).showSnackBar(
-          SnackBar(content: Text('连接失败：$e'), backgroundColor: AppColors.error),
-        );
+        AppToast.show(context, '连接失败：$e', type: AppToastType.error);
         unawaited(_startScan());
       }
     } finally {
@@ -334,6 +326,38 @@ class _DeviceScanPageState extends ConsumerState<DeviceScanPage>
     }
     return true;
   }
+
+  Future<bool> _ensureBlePermissions() async {
+    final statuses = await [
+      Permission.bluetoothScan,
+      Permission.bluetoothConnect,
+    ].request();
+    final granted = statuses.values.every((status) => status.isGranted);
+    if (granted) return true;
+    if (!mounted) return false;
+    AppToast.show(context, '请开启蓝牙权限后再搜索设备', type: AppToastType.warning);
+    await showDialog<void>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('需要蓝牙权限'),
+        content: const Text('搜索和连接健康设备需要蓝牙权限，请在系统设置中开启后重试。'),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(ctx),
+            child: const Text('稍后再说'),
+          ),
+          TextButton(
+            onPressed: () {
+              Navigator.pop(ctx);
+              openAppSettings();
+            },
+            child: const Text('去设置'),
+          ),
+        ],
+      ),
+    );
+    return false;
+  }
 }
 
 class _ScanningEmpty extends StatelessWidget {