feat(AuthService): assign admin role to the first registered user and clean up admin user creation logic

Services/Auth/AuthService.cs

@@ -27,7 +27,6 @@ public class AuthService(IDbContextFactory<MyDbContext> dbContextFactory, IConfi
         {
             return (false, "该用户名已被使用", null);
         }
-
         var user = new User
         {
             UserName = request.UserName,
@@ -36,6 +35,11 @@ public class AuthService(IDbContextFactory<MyDbContext> dbContextFactory, IConfi
             CreatedAt = DateTime.UtcNow,
             UpdatedAt = DateTime.UtcNow
         };
+        var userCount = await context.Users.CountAsync();
+        if (userCount == 0)
+        {
+            user.RoleId = 1;
+        }
         context.Users.Add(user);
         await context.SaveChangesAsync();
         return (true, "用户注册成功", user);
@@ -277,7 +281,7 @@ public class AuthService(IDbContextFactory<MyDbContext> dbContextFactory, IConfi
         }
 
         var (isSuccess, message, user) = await FindOrCreateGitHubUserAsync(githubUserId, name ?? loginName, email);
-        
+
         if (!isSuccess || user == null)
         {
             Console.WriteLine($"创建或查找GitHub用户失败: {message}");

Services/Initializer/DatabaseInitializer.cs

@@ -91,33 +91,7 @@ public class DatabaseInitializer(
             await context.Roles.AddAsync(adminRole);
             await context.SaveChangesAsync();
         }
-
+        logger.LogInformation("请注意，第一个注册的用户将自动成为管理员");
-        // 检查并创建管理员用户
-        var adminUser = await context.Users.FirstOrDefaultAsync(u => u.UserName == "Admin");
-        if (adminUser == null)
-        {
-            // 生成随机6位密码
-            string password = GenerateRandomPassword(6);
-            string passwordHash = HashPassword(password);
-
-            logger.LogInformation("创建管理员用户，邮箱: you@foxel.cc，密码: {Password}", password);
-            adminUser = new User
-            {
-                UserName = "Admin",
-                Email = "you@foxel.cc",
-                PasswordHash = passwordHash,
-                RoleId = adminRole.Id,
-                CreatedAt = DateTime.UtcNow,
-                UpdatedAt = DateTime.UtcNow
-            };
-            await context.Users.AddAsync(adminUser);
-
-            Console.ForegroundColor = ConsoleColor.Yellow;
-            Console.WriteLine($"[重要] 管理员账户初始密码: {password}，请及时修改");
-            Console.WriteLine($"[重要] 请及时登录后台修改AI相关配置，系统才可正常运行");
-            Console.ResetColor();
-            await context.SaveChangesAsync();
-        }
     }
 
     private string GenerateRandomPassword(int length)