feat: 控制台浏览器远控面板

- TaskDetailPanel 新增“浏览器”页签，内嵌 BrowserPanel。
- 开始观看：fetch + ReadableStream 读 SSE（EventSource 发不出
  X-API-Key），最新帧以 data URI 显示；状态每 5 秒轮询。
- 接管/交还：POST /browser/control；接管后点画面按 1280x800
  换算坐标 POST /browser/input，键盘直达页面。
- 产物：cloud/console.html 由 vite 单文件构建重打（341451 字节，
  含 browser/state 与“浏览器远控”标记）。

cloud/console-react/src/api/paths.ts

@@ -56,6 +56,10 @@ export const paths = {
   taskThreads: (id: string) => "/tasks/" + enc(id) + "/threads",
   taskThreadAction: (id: string, kind: string) => "/tasks/" + enc(id) + "/thread/" + kind,
   taskCost: (id: string) => "/tasks/" + enc(id) + "/cost",
+  taskBrowserState: (id: string) => "/tasks/" + enc(id) + "/browser/state",
+  taskBrowserStream: (id: string) => "/tasks/" + enc(id) + "/browser/stream",
+  taskBrowserInput: (id: string) => "/tasks/" + enc(id) + "/browser/input",
+  taskBrowserControl: (id: string) => "/tasks/" + enc(id) + "/browser/control",
   uploads: "/uploads",
   adminQuotas: "/admin/quotas",
   adminQuotaUser: (uid: string) => "/admin/quotas?user_id=" + enc(uid),