feat: Agent采集uptime, 后端持久化kernel/uptime/diskIO, 前端磁盘BPS+IOPS展示

- Agent: system.go 添加 readUptime(), SystemStat 携带 Uptime
- Backend: Server 模型新增 Kernel 字段, ReceiveReport 持久化 kernel+uptime
- Backend: /agent/latest 返回 kernel/uptime/port_info/disk_io_info/disk_total
- Frontend: 磁盘监控改为 BPS+IOPS (4张卡片), 系统信息修复内核/运行时长/监听端口/磁盘容量
- 图表单位从 MB/s 改为 KB/s, 添加 formatBPS 工具函数

backend/internal/api/handlers/server.go

@@ -5,6 +5,7 @@ import (
 	"strconv"
 
 	"ezops/internal/models"
+	"ezops/pkg/crypto"
 
 	"github.com/gin-gonic/gin"
 	"gorm.io/gorm"
@@ -12,12 +13,13 @@ import (
 
 // ServerHandler 服务器处理器
 type ServerHandler struct {
-	db *gorm.DB
+	db    *gorm.DB
+	crypt *crypto.SecretBox
 }
 
 // NewServerHandler 创建服务器处理器
-func NewServerHandler(db *gorm.DB) *ServerHandler {
-	return &ServerHandler{db: db}
+func NewServerHandler(db *gorm.DB, masterKey string) *ServerHandler {
+	return &ServerHandler{db: db, crypt: crypto.NewSecretBox(masterKey)}
 }
 
 // recordServerAudit 记录服务器操作审计日志 // Logan.Li
@@ -91,6 +93,11 @@ func (h *ServerHandler) ListServers(c *gin.Context) {
 		Order("created_at DESC").
 		Find(&servers)
 
+	// 填充 has_auth 字段（密码和SSH密钥在JSON中隐藏，但前端需知道是否有凭据） // Logan.Li
+	for i := range servers {
+		servers[i].HasAuth = servers[i].Password != "" || servers[i].SSHKey != ""
+	}
+
 	c.JSON(http.StatusOK, models.Response{
 		Code:    200,
 		Message: "success",
@@ -324,7 +331,11 @@ func (h *ServerHandler) DeleteServer(c *gin.Context) {
 		return
 	}
 
-	if err := h.db.Delete(&models.Server{}, id).Error; err != nil {
+	// 硬删除：先清理关联数据，再物理删除服务器记录
+	h.db.Unscoped().Where("hostname = ?", server.Hostname).Delete(&models.AgentReport{})
+	h.db.Unscoped().Where("hostname = ?", server.Hostname).Delete(&models.MetricsAggregate{})
+
+	if err := h.db.Unscoped().Delete(&models.Server{}, id).Error; err != nil {
 		c.JSON(http.StatusInternalServerError, models.Response{
 			Code:    500,
 			Message: "删除失败",
@@ -333,10 +344,9 @@ func (h *ServerHandler) DeleteServer(c *gin.Context) {
 	}
 
 	h.recordServerAudit(c, "delete", server.Hostname+" ("+server.IP+")", strconv.Itoa(int(server.ID)), 1, "")
-
 	c.JSON(http.StatusOK, models.Response{
 		Code:    200,
-		Message: "删除成功",
+		Message: "服务器已彻底删除",
 	})
 }