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/rdp/packet_io.go

@@ -0,0 +1,77 @@
+package rdp
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"ezops/pkg/rdp/transport"
+)
+
+const (
+	fastPathActionFastPath = 0x0
+	fastPathActionX224     = 0x3
+)
+
+// WirePacket 表示从 RDP 连接读取到的一层帧 // Logan.Li
+type WirePacket struct {
+	FastPath bool
+	SecFlag  byte
+	Payload  []byte
+}
+
+// ReadWirePacket 读取 TPKT/X.224 或 FastPath 输出帧 // Logan.Li
+func ReadWirePacket(r io.Reader) (WirePacket, error) {
+	var hdr [2]byte
+	if _, err := io.ReadFull(r, hdr[:]); err != nil {
+		return WirePacket{}, err
+	}
+	version := hdr[0]
+	if version == fastPathActionX224 {
+		var extHdr [2]byte
+		if _, err := io.ReadFull(r, extHdr[:]); err != nil {
+			return WirePacket{}, err
+		}
+		size := binary.BigEndian.Uint16(extHdr[:])
+		if size < 4 {
+			return WirePacket{}, fmt.Errorf("TPKT 长度非法: %d", size)
+		}
+		body := make([]byte, int(size)-4)
+		if _, err := io.ReadFull(r, body); err != nil {
+			return WirePacket{}, err
+		}
+		if len(body) < 3 || body[1] != 0xF0 {
+			return WirePacket{}, fmt.Errorf("非 X.224 Data PDU")
+		}
+		return WirePacket{Payload: body[3:]}, nil
+	}
+	secFlag := (version >> 6) & 0x3
+	length := int(hdr[1])
+	packetSize := 0
+	if length&0x80 != 0 {
+		var extByte [1]byte
+		if _, err := io.ReadFull(r, extByte[:]); err != nil {
+			return WirePacket{}, err
+		}
+		packetSize = ((length &^ 0x80) << 8) + int(extByte[0]) - 3
+	} else {
+		packetSize = length - 2
+	}
+	if packetSize < 0 {
+		return WirePacket{FastPath: true, SecFlag: secFlag}, nil
+	}
+	body := make([]byte, packetSize)
+	if _, err := io.ReadFull(r, body); err != nil {
+		return WirePacket{}, err
+	}
+	return WirePacket{FastPath: true, SecFlag: secFlag, Payload: body}, nil
+}
+
+// WriteFastPathInput 发送 Fast-Path Input 事件批次 // Logan.Li
+func WriteFastPathInput(w io.Writer, events []byte) error {
+	hdr := uint16(len(events)+3) | 0x8000
+	frame := make([]byte, 0, len(events)+3)
+	frame = append(frame, fastPathActionFastPath|0x04, byte(hdr>>8), byte(hdr))
+	frame = append(frame, events...)
+	return transport.WriteRaw(w, frame)
+}