feat: 云账号创建表单 — 修复凭证反序列化bug + 添加账号弹窗

- 后端: 重构 CreateCloudAccount 用独立 createCloudAccountRequest struct，
  修复 AccessKey/SecretKey 因 json:"-" 导致反序列化被跳过、凭证永远为空的 bug (Go Pitfall #8)
- 前端: 添加账号按钮接入 Dialog 表单 (名称/云平台/AccessKey/SecretKey/月费用/状态)，
  移除无 handler 的刷新/编辑按钮，新增名称必填校验

backend/internal/api/handlers/server.go

@@ -3,6 +3,7 @@ package handlers
 import (
 	"net/http"
 	"strconv"
+	"strings"
 
 	"ezops/internal/models"
 
@@ -401,6 +402,16 @@ func (h *CloudAccountHandler) ListCloudAccounts(c *gin.Context) {
 	})
 }
 
+// createCloudAccountRequest 创建云账号请求（独立 request struct，避免 CloudAccount.AccessKey/SecretKey 的 json:"-" 导致无法反序列化）
+type createCloudAccountRequest struct {
+	Name        string  `json:"name"`
+	Provider    string  `json:"provider"`
+	AccessKey   string  `json:"access_key"`
+	SecretKey   string  `json:"secret_key"`
+	MonthlyCost float64 `json:"monthly_cost"`
+	Status      string  `json:"status"`
+}
+
 // CreateCloudAccount 创建云账号
 // @Summary 创建云账号
 // @Description 创建新云账号
@@ -408,12 +419,12 @@ func (h *CloudAccountHandler) ListCloudAccounts(c *gin.Context) {
 // @Accept json
 // @Produce json
 // @Security Bearer
-// @Param request body models.CloudAccount true "创建请求"
+// @Param request body createCloudAccountRequest true "创建请求"
 // @Success 200 {object} models.Response{data=models.CloudAccount}
 // @Router /cloud-accounts [post]
 func (h *CloudAccountHandler) CreateCloudAccount(c *gin.Context) {
-	var account models.CloudAccount
-	if err := c.ShouldBindJSON(&account); err != nil {
+	var req createCloudAccountRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
 		c.JSON(http.StatusBadRequest, models.Response{
 			Code:    400,
 			Message: "请求参数错误: " + err.Error(),
@@ -421,6 +432,28 @@ func (h *CloudAccountHandler) CreateCloudAccount(c *gin.Context) {
 		return
 	}
 
+	if strings.TrimSpace(req.Name) == "" || strings.TrimSpace(req.Provider) == "" {
+		c.JSON(http.StatusBadRequest, models.Response{
+			Code:    400,
+			Message: "账号名称和云平台不能为空",
+		})
+		return
+	}
+
+	status := strings.TrimSpace(req.Status)
+	if status == "" {
+		status = "active"
+	}
+
+	account := models.CloudAccount{
+		Name:        strings.TrimSpace(req.Name),
+		Provider:    strings.TrimSpace(req.Provider),
+		AccessKey:   req.AccessKey,
+		SecretKey:   req.SecretKey,
+		MonthlyCost: req.MonthlyCost,
+		Status:      status,
+	}
+
 	if err := h.db.Create(&account).Error; err != nil {
 		c.JSON(http.StatusInternalServerError, models.Response{
 			Code:    500,