feat: 文件存储安全加固 + 认证增强 + 媒体URL保护 + provider 重构

## 后端安全加固
- 新增 UserUploadPathResolver: 用户上传文件路径安全解析, 防目录穿越
- LocalReportFileStorage: 文件存储路径安全加固
- local_account_file_cleanup: 账号删除时文件清理逻辑增强
- AuthService: 认证逻辑增强
- file_endpoints / report_endpoints: 文件访问接口安全加固
- ai_chat_endpoints / doctor_endpoints: 接口安全调整
- Program.cs: 服务注册调整

## 前端认证与媒体
- 新增 authenticated_network_image.dart: 带认证的图片加载组件
- auth_provider: 认证状态管理大幅增强(+173)
- api_client: 网络客户端增强(+124)
- chat_provider: 聊天 provider 重构(+76)
- omron_device_provider: 蓝牙设备 provider 增强(+53)
- sse_handler: SSE 处理增强(+35)
- consultation_provider / data_providers / conversation_history_provider: 调整

## 页面调整
- remaining_pages: 健康档案/饮食记录等页面增强(+115)
- home_page / chat_messages_view: 主页微调
- doctor 端多页微调(consultations/dashboard/followups/patient_detail/profile/report_detail/reports)
- report_pages / settings_pages / notification_prefs_page: 微调
- device_scan_page / diet_capture_page / admin_home_page: 微调

## 测试
- 新增 file_path_security_tests: 文件路径安全测试
- 新增 protected_media_url_test: 媒体URL保护测试
- 新增 user_session_identity_test: 用户会话身份测试
- account_deletion_tests / application_service_tests / auth_tests: 更新

backend/src/Health.Infrastructure/Auth/AuthService.cs

@@ -88,14 +88,39 @@ public sealed class AuthService(
         {
             var tokens = AddTokens(AdminId, AdminPhone, "Admin");
             await _db.SaveChangesAsync(ct);
-            return new AuthResult(0, new { tokens.accessToken, tokens.refreshToken, user = new { role = "Admin" } });
+            return new AuthResult(0, new
+            {
+                tokens.accessToken,
+                tokens.refreshToken,
+                user = new
+                {
+                    id = AdminId,
+                    phone = AdminPhone,
+                    role = "Admin",
+                    name = "管理员"
+                }
+            });
         }
 
         var user = await _db.Users.FindAsync([oldToken.UserId], ct);
         if (user == null) return Error(40002, "用户不存在");
         var userTokens = AddTokens(user.Id, user.Phone, user.Role);
         await _db.SaveChangesAsync(ct);
-        return new AuthResult(0, new { userTokens.accessToken, userTokens.refreshToken, user = new { user.Role } });
+        return new AuthResult(0, new
+        {
+            userTokens.accessToken,
+            userTokens.refreshToken,
+            user = new
+            {
+                user.Id,
+                user.Phone,
+                user.Role,
+                user.Name,
+                user.Gender,
+                user.AvatarUrl,
+                BirthDate = user.BirthDate?.ToString("yyyy-MM-dd")
+            }
+        });
     }
 
     public async Task LogoutAsync(string refreshToken, CancellationToken ct)