feat: LokiDeploy 初始提交 - 轻量级 K8s Loki 部署平台

Go(Gin) + React(Vite + shadcn/ui + Tailwind) 前后端分离，全中文 UI

- 集群管理：Kubeconfig / Token 双接入，kubectl + helm 部署
- 主机管理：SSH 密钥 / 密码双认证，CPU/内存/磁盘使用率监控，SSH 错误中文友好提示
- 存储配置、部署管理、系统设置
- Docker 镜像内置 kubectl + helm，开箱即用
- run.sh 一键启停（start/stop/restart/status）

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

backend/services/auth.go

@@ -0,0 +1,83 @@
+package services
+
+import (
+	"lokideploy/models"
+	"lokideploy/utils"
+)
+
+type AuthService struct{}
+
+func NewAuthService() *AuthService {
+	return &AuthService{}
+}
+
+func (s *AuthService) Login(username, password string) (*models.User, string, error) {
+	db := models.GetDB()
+	db.RLock()
+	defer db.RUnlock()
+	for i := range db.Users {
+		if db.Users[i].Username == username {
+			if !utils.VerifyPassword(password, db.Users[i].Password) {
+				return nil, "", utils.ErrInvalidCredentials
+			}
+			token, err := utils.GenerateToken(db.Users[i].ID, db.Users[i].Username, db.Users[i].Role)
+			if err != nil {
+				return nil, "", err
+			}
+			return &db.Users[i], token, nil
+		}
+	}
+	return nil, "", utils.ErrInvalidCredentials
+}
+
+func (s *AuthService) Register(username, password, nickname, role string) (*models.User, error) {
+	hash, err := utils.HashPassword(password)
+	if err != nil {
+		return nil, err
+	}
+	user := &models.User{
+		ID:       models.GetDB().NextID("users"),
+		Username: username,
+		Password: hash,
+		Nickname: nickname,
+		Role:     role,
+	}
+	if err := models.GetDB().CreateUser(user); err != nil {
+		return nil, err
+	}
+	return user, nil
+}
+
+func (s *AuthService) GetUserByID(id uint) (*models.User, error) {
+	db := models.GetDB()
+	db.RLock()
+	defer db.RUnlock()
+	for i := range db.Users {
+		if db.Users[i].ID == id {
+			u := db.Users[i]
+			return &u, nil
+		}
+	}
+	return nil, utils.ErrNotFound
+}
+
+func (s *AuthService) ChangePassword(userID uint, oldPassword, newPassword string) error {
+	db := models.GetDB()
+	db.Lock()
+	defer db.Unlock()
+	for i := range db.Users {
+		if db.Users[i].ID == userID {
+			if !utils.VerifyPassword(oldPassword, db.Users[i].Password) {
+				return utils.ErrInvalidCredentials
+			}
+			hash, err := utils.HashPassword(newPassword)
+			if err != nil {
+				return err
+			}
+			db.Users[i].Password = hash
+			go db.Save()
+			return nil
+		}
+	}
+	return utils.ErrNotFound
+}