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>

frontend/src/components/common/PageShell.tsx

@@ -0,0 +1,79 @@
+import type { ReactNode } from "react"
+
+import { cn } from "@/lib/utils"
+
+type PageShellProps = {
+  children: ReactNode
+  className?: string
+}
+
+type PageHeaderProps = {
+  title: ReactNode
+  description?: ReactNode
+  actions?: ReactNode
+  className?: string
+}
+
+type PageSectionProps = {
+  children: ReactNode
+  title?: ReactNode
+  description?: ReactNode
+  actions?: ReactNode
+  className?: string
+  contentClassName?: string
+}
+
+export function PageShell({ children, className }: PageShellProps) {
+  return (
+    <main className={cn("flex min-h-0 w-full flex-col gap-4 p-4 md:p-6", className)}>
+      {children}
+    </main>
+  )
+}
+
+export function PageHeader({ title, description, actions, className }: PageHeaderProps) {
+  return (
+    <header className={cn("flex flex-col gap-3 md:flex-row md:items-start md:justify-between", className)}>
+      <div className="min-w-0 space-y-1">
+        <h1 className="truncate text-xl font-semibold tracking-normal text-[var(--dg-text-primary)] md:text-2xl">
+          {title}
+        </h1>
+        {description ? (
+          <p className="max-w-3xl text-sm leading-6 text-[var(--dg-text-secondary)]">{description}</p>
+        ) : null}
+      </div>
+      {actions ? <div className="flex shrink-0 flex-wrap items-center gap-2">{actions}</div> : null}
+    </header>
+  )
+}
+
+export function PageSection({
+  children,
+  title,
+  description,
+  actions,
+  className,
+  contentClassName,
+}: PageSectionProps) {
+  const hasHeader = title || description || actions
+
+  return (
+    <section
+      className={cn(
+        "rounded-lg border border-[var(--dg-border)] bg-[var(--dg-bg-secondary)] shadow-[var(--shadow-card)]",
+        className,
+      )}
+    >
+      {hasHeader ? (
+        <div className="flex flex-col gap-3 border-b border-[var(--dg-border)] px-4 py-3 md:flex-row md:items-center md:justify-between">
+          <div className="min-w-0 space-y-1">
+            {title ? <h2 className="truncate text-base font-medium text-[var(--dg-text-primary)]">{title}</h2> : null}
+            {description ? <p className="text-sm text-[var(--dg-text-secondary)]">{description}</p> : null}
+          </div>
+          {actions ? <div className="flex shrink-0 flex-wrap items-center gap-2">{actions}</div> : null}
+        </div>
+      ) : null}
+      <div className={cn("min-w-0 p-4", contentClassName)}>{children}</div>
+    </section>
+  )
+}