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/controller/rdp_live.go

@@ -0,0 +1,74 @@
+package controller
+
+import (
+	"sync"
+
+	rdpengine "ezops/pkg/rdp"
+)
+
+// rdpLiveBroadcaster 将 RDP 主会话帧广播给审计实时查看端，慢消费者会丢旧帧保最新。 // Logan.Li
+type rdpLiveBroadcaster struct {
+	mu      sync.Mutex
+	closed  bool
+	clients map[chan rdpengine.ServerFrame]struct{}
+}
+
+func newRDPLiveBroadcaster() *rdpLiveBroadcaster {
+	return &rdpLiveBroadcaster{clients: make(map[chan rdpengine.ServerFrame]struct{})}
+}
+
+func (b *rdpLiveBroadcaster) subscribe() chan rdpengine.ServerFrame {
+	ch := make(chan rdpengine.ServerFrame, 8)
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if b.closed {
+		close(ch)
+		return ch
+	}
+	b.clients[ch] = struct{}{}
+	return ch
+}
+
+func (b *rdpLiveBroadcaster) unsubscribe(ch chan rdpengine.ServerFrame) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if _, ok := b.clients[ch]; ok {
+		delete(b.clients, ch)
+		close(ch)
+	}
+}
+
+func (b *rdpLiveBroadcaster) publish(frame rdpengine.ServerFrame) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if b.closed {
+		return
+	}
+	for ch := range b.clients {
+		select {
+		case ch <- frame:
+		default:
+			select {
+			case <-ch:
+			default:
+			}
+			select {
+			case ch <- frame:
+			default:
+			}
+		}
+	}
+}
+
+func (b *rdpLiveBroadcaster) close() {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if b.closed {
+		return
+	}
+	b.closed = true
+	for ch := range b.clients {
+		delete(b.clients, ch)
+		close(ch)
+	}
+}