feat: Redis cluster support + version auto-detect + metrics API

backend/internal/handler/auth.go

@@ -67,9 +67,12 @@ func Login(c *gin.Context) {
 			c.JSON(http.StatusUnauthorized, gin.H{"detail": "Invalid username or password"})
 			return
 		}
-		// LDAP 认证成功，自动创建本地用户
+		// LDAP 认证成功，自动创建或恢复本地用户
 		isActive := true
 		defaultRole := "developer"
+		if ldapInfo.DisplayName == "" {
+			ldapInfo.DisplayName = ldapInfo.Username
+		}
 		newUser := model.User{
 			Username:       ldapInfo.Username,
 			DisplayName:    ldapInfo.DisplayName,
@@ -79,20 +82,25 @@ func Login(c *gin.Context) {
 			Role:           defaultRole,
 			IsActive:       &isActive,
 		}
-		if newUser.DisplayName == "" {
-			newUser.DisplayName = newUser.Username
+		// FirstOrCreate: 不存在则创建，已存在则获取（避免 uniqueIndex 冲突）
+		result := model.DB.Where("username = ?", ldapInfo.Username).FirstOrCreate(&newUser)
+		if result.Error != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"detail": "Failed to create LDAP user: " + result.Error.Error()})
+			return
 		}
-		if createErr := model.DB.Create(&newUser).Error; createErr != nil {
-			// 可能并发创建冲突，再查一次
-			model.DB.Where("username = ?", ldapInfo.Username).First(&user)
-			if user.ID == 0 {
-				c.JSON(http.StatusInternalServerError, gin.H{"detail": "Failed to create LDAP user"})
-				return
+		// 更新已有用户的 display_name / email（LDAP 信息可能变更）
+		if newUser.ID != 0 {
+			updates := map[string]interface{}{
+				"display_name": ldapInfo.DisplayName,
+				"auth_source":  "ldap",
+				"is_active":    true,
 			}
-		} else {
-			user = newUser
+			if ldapInfo.Email != nil {
+				updates["email"] = *ldapInfo.Email
+			}
+			model.DB.Model(&newUser).Updates(updates)
 		}
-		// 记录 auth_source
+		user = newUser
 	} else {
 		c.JSON(http.StatusInternalServerError, gin.H{"detail": "Database error"})
 		return