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/credential.go

@@ -0,0 +1,160 @@
+package handlers
+
+import (
+	"net/http"
+	"strconv"
+
+	"ezops/internal/models"
+	"ezops/pkg/crypto"
+
+	"github.com/gin-gonic/gin"
+	"gorm.io/gorm"
+)
+
+// CredentialHandler 凭据管理处理器 // Logan.Li
+type CredentialHandler struct {
+	db    *gorm.DB
+	crypt *crypto.SecretBox
+}
+
+func NewCredentialHandler(db *gorm.DB, masterKey string) *CredentialHandler {
+	return &CredentialHandler{
+		db:    db,
+		crypt: crypto.NewSecretBox(masterKey),
+	}
+}
+
+// preview 内容脱敏预览：前8字符 + ... + 后4字符
+func preview(s string) string {
+	if len(s) <= 12 {
+		return "****"
+	}
+	return s[:8] + "..." + s[len(s)-4:]
+}
+
+// ListCredentials 凭据列表
+func (h *CredentialHandler) ListCredentials(c *gin.Context) {
+	var creds []models.Credential
+	if err := h.db.Order("updated_at DESC").Find(&creds).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "查询失败"})
+		return
+	}
+	items := make([]models.CredentialListResponse, 0, len(creds))
+	for _, cred := range creds {
+		items = append(items, models.CredentialListResponse{
+			ID:          cred.ID,
+			Name:        cred.Name,
+			Type:        cred.Type,
+			Preview:     preview(cred.Content),
+			Description: cred.Description,
+			CreatedAt:   cred.CreatedAt,
+			UpdatedAt:   cred.UpdatedAt,
+		})
+	}
+	c.JSON(http.StatusOK, models.Response{Code: 200, Data: models.ListResponse{
+		List: items, Total: int64(len(items)),
+	}})
+}
+
+// CreateCredential 创建凭据
+func (h *CredentialHandler) CreateCredential(c *gin.Context) {
+	var req models.CredentialCreateRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "参数错误: " + err.Error()})
+		return
+	}
+
+	encrypted, err := h.crypt.Encrypt(req.Content)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "加密失败"})
+		return
+	}
+
+	cred := models.Credential{
+		Name:        req.Name,
+		Type:        req.Type,
+		Content:     encrypted,
+		Description: req.Description,
+	}
+	if err := h.db.Create(&cred).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "创建失败"})
+		return
+	}
+
+	c.JSON(http.StatusOK, models.Response{
+		Code:    200,
+		Message: "创建成功",
+		Data: models.CredentialListResponse{
+			ID:          cred.ID,
+			Name:        cred.Name,
+			Type:        cred.Type,
+			Preview:     preview(cred.Content),
+			Description: cred.Description,
+			CreatedAt:   cred.CreatedAt,
+			UpdatedAt:   cred.UpdatedAt,
+		},
+	})
+}
+
+// UpdateCredential 更新凭据
+func (h *CredentialHandler) UpdateCredential(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "无效ID"})
+		return
+	}
+
+	var req models.CredentialUpdateRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "参数错误: " + err.Error()})
+		return
+	}
+
+	var cred models.Credential
+	if h.db.First(&cred, id).Error != nil {
+		c.JSON(http.StatusNotFound, models.Response{Code: 404, Message: "凭据不存在"})
+		return
+	}
+
+	cred.Name = req.Name
+	cred.Type = req.Type
+	cred.Description = req.Description
+
+	if req.Content != "" {
+		encrypted, err := h.crypt.Encrypt(req.Content)
+		if err != nil {
+			c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "加密失败"})
+			return
+		}
+		cred.Content = encrypted
+	}
+
+	if err := h.db.Save(&cred).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "更新失败"})
+		return
+	}
+
+	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "更新成功"})
+}
+
+// DeleteCredential 删除凭据
+func (h *CredentialHandler) DeleteCredential(c *gin.Context) {
+	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "无效ID"})
+		return
+	}
+
+	var cred models.Credential
+	if h.db.First(&cred, id).Error != nil {
+		c.JSON(http.StatusNotFound, models.Response{Code: 404, Message: "凭据不存在"})
+		return
+	}
+
+	if err := h.db.Delete(&cred).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "删除失败"})
+		return
+	}
+
+	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "删除成功"})
+}