feat(rdp): 新增 RDP 远程桌面/SMB/账单同步能力 + 清理编译产物

主要变更：
- RDP 远程桌面：新增 backend/pkg/rdp（RDP 引擎 + credssp/display/rle/trace）、
  backend/controller/rdp*（连接/凭证/文件/会话/实时）、frontend RDP 组件与 API
- Windows SMB 文件传输：backend/pkg/winsmb
- 云账单同步：backend/pkg/billingsync + billing_sync/aliyun_billing，前端账单详情
- Agent CLI Kubernetes 工具：kubernetes_action/get、pod_execute/logs
- 服务器导入助手：server_import_helpers、ImportCredentialSettings
- 国际化与组件重构（cloud/deploy/monitor/server/system 等多模块）
- 清理编译产物二进制：移除 backend/server、backend/agent/bin/aiops-agent-*
- .gitignore：新增 backend/agent/ 与 .cache/（避免 334MB go-build 缓存误入库）

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

backend/pkg/billingsync/sync.go

@@ -0,0 +1,141 @@
+// 云账单同步引擎 — 从云账号 AK 拉取日账单写入本地 // Logan.Li
+package billingsync
+
+import (
+	"fmt"
+	"time"
+
+	"ezops/cloud"
+	"ezops/model"
+
+	"gorm.io/gorm"
+)
+
+// Result 同步结果
+type Result struct {
+	BillingDate string   `json:"billing_date"`
+	Accounts    int      `json:"accounts"`
+	Created     int      `json:"created"`
+	Updated     int      `json:"updated"`
+	Skipped     int      `json:"skipped"`
+	Errors      []string `json:"errors"`
+}
+
+// Yesterday 昨日日期 YYYY-MM-DD
+func Yesterday() string {
+	return time.Now().AddDate(0, 0, -1).Format("2006-01-02")
+}
+
+// SyncDate 同步指定日期账单（全部或单个活跃云账号）
+func SyncDate(db *gorm.DB, billingDate string, accountID *uint) Result {
+	result := Result{
+		BillingDate: billingDate,
+		Errors:      []string{},
+	}
+
+	var accounts []model.CloudAccount
+	q := db.Where("status = ?", "active")
+	if accountID != nil {
+		q = q.Where("id = ?", *accountID)
+	}
+	q.Find(&accounts)
+	result.Accounts = len(accounts)
+
+	if len(accounts) == 0 {
+		result.Errors = append(result.Errors, "没有可同步的活跃云账号")
+		return result
+	}
+
+	for _, account := range accounts {
+		created, updated, skipped, err := syncAccount(db, account, billingDate)
+		result.Created += created
+		result.Updated += updated
+		result.Skipped += skipped
+		if err != nil {
+			result.Errors = append(result.Errors, fmt.Sprintf("%s(%s): %s", account.Name, account.Provider, err.Error()))
+		}
+	}
+	return result
+}
+
+// SummaryMessage 生成执行摘要文案
+func SummaryMessage(r Result) string {
+	msg := fmt.Sprintf("%s 新增 %d 条，更新 %d 条", r.BillingDate, r.Created, r.Updated)
+	if len(r.Errors) > 0 {
+		msg += fmt.Sprintf("；%d 个账号异常", len(r.Errors))
+	}
+	return msg
+}
+
+func syncAccount(db *gorm.DB, account model.CloudAccount, billingDate string) (created, updated, skipped int, err error) {
+	fetcher := cloud.NewBillingFetcher(account.Provider, account.AccessKey, account.SecretKey)
+	if fetcher == nil {
+		return 0, 0, 0, fmt.Errorf("暂不支持该云厂商账单同步")
+	}
+
+	records, err := fetcher.FetchDailyBill(billingDate)
+	if err != nil {
+		return 0, 0, 0, err
+	}
+	if len(records) == 0 {
+		return 0, 0, 1, fmt.Errorf("该日期暂无账单数据（可能尚未出账）")
+	}
+
+	accountID := account.ID
+	accountName := account.Name
+
+	for _, rec := range records {
+		var existing model.CloudBilling
+		findErr := db.Where(
+			"cloud_account_id = ? AND billing_date = ? AND provider = ? AND service = ? AND region = ?",
+			accountID, billingDate, rec.Provider, rec.Service, rec.Region,
+		).Take(&existing).Error
+
+		if findErr == gorm.ErrRecordNotFound {
+			row := model.CloudBilling{
+				CloudAccountID: &accountID,
+				AccountName:    accountName,
+				Provider:       rec.Provider,
+				BillingDate:    billingDate,
+				Cost:           rec.Cost,
+				Currency:       rec.Currency,
+				Service:        rec.Service,
+				Region:         rec.Region,
+				Description:    rec.Description,
+			}
+			if row.Currency == "" {
+				row.Currency = "CNY"
+			}
+			if db.Create(&row).Error == nil {
+				created++
+			} else {
+				skipped++
+			}
+			continue
+		}
+		if findErr != nil {
+			skipped++
+			continue
+		}
+
+		if db.Model(&existing).Updates(map[string]interface{}{
+			"cost":         rec.Cost,
+			"currency":     rec.Currency,
+			"description":  rec.Description,
+			"account_name": accountName,
+		}).Error == nil {
+			updated++
+		} else {
+			skipped++
+		}
+	}
+
+	monthStart := billingDate[:7] + "-01"
+	var monthCost float64
+	db.Model(&model.CloudBilling{}).
+		Where("cloud_account_id = ? AND billing_date >= ?", accountID, monthStart).
+		Select("COALESCE(SUM(cost), 0)").Scan(&monthCost)
+	db.Model(&account).Update("monthly_cost", monthCost)
+
+	return created, updated, skipped, nil
+}