Harden WebCRT interactive sessions for more CRT-like device login.

Improve async connect, binary stdout coalescing, paste throttling with progress, SSH keepalive, login prompt settle, and optional SFTP while keeping core terminal UX focused.

Co-authored-by: Cursor <cursoragent@cursor.com>

web/src/i18n/en.ts

@@ -939,6 +939,25 @@ const en = {
       copied: "Copied to clipboard",
       copyEmpty: "Terminal is empty",
       copyFailed: "Copy failed",
+      break: "Break",
+      breakSent: "Break sent",
+      broadcast: "Broadcast",
+      broadcastSent: "Sent to all sessions",
+      postLogin: "Post-login cmds",
+    },
+    favorites: "Favorites",
+    recent: "Recent",
+    favorite: "Toggle favorite",
+    encoding: "Encoding",
+    fontSize: "Font",
+    broadcastPh: "Send to all tabs…",
+    buttonBarHint: "One per line: label|command",
+    postLoginPrompt: "Post-login commands (one per line, this device)",
+    postLoginSaved: "Post-login commands saved",
+    sftp: {
+      refresh: "Refresh",
+      upload: "Upload",
+      uploaded: "Upload complete",
     },
     err: {
       sessionLimit: "Session limit reached; close other terminals first",
@@ -946,6 +965,8 @@ const en = {
       credsIncomplete: "Incomplete username/password on this NE",
       cliProfile: "UME NEs require a CLI connect profile (default account / hop)",
       connectFailed: "Device login failed: {{detail}}",
+      sftpHop: "SFTP does not support hop devices yet (direct SSH only)",
+      sftpSsh: "SFTP requires SSH",
     },
   },
   topology: {

web/src/i18n/zh.ts

@@ -936,6 +936,25 @@ const zh = {
       copied: "已复制到剪贴板",
       copyEmpty: "终端内容为空",
       copyFailed: "复制失败",
+      break: "Break",
+      breakSent: "已发送 Break",
+      broadcast: "广播",
+      broadcastSent: "已广播到全部会话",
+      postLogin: "登录后命令",
+    },
+    favorites: "收藏",
+    recent: "最近",
+    favorite: "收藏/取消",
+    encoding: "编码",
+    fontSize: "字号",
+    broadcastPh: "发送到全部标签…",
+    buttonBarHint: "每行：按钮名|命令",
+    postLoginPrompt: "登录后自动执行（每行一条，仅本设备）",
+    postLoginSaved: "登录后命令已保存",
+    sftp: {
+      refresh: "刷新",
+      upload: "上传",
+      uploaded: "上传成功",
     },
     err: {
       sessionLimit: "并发会话已达上限，请先关闭其他终端",
@@ -943,6 +962,8 @@ const zh = {
       credsIncomplete: "网元账号或密码不完整",
       cliProfile: "UME 网元需要先配置 CLI 连接模板（默认账号/跳板）",
       connectFailed: "登录设备失败：{{detail}}",
+      sftpHop: "SFTP 暂不支持跳板设备，请使用直连 SSH",
+      sftpSsh: "SFTP 仅支持 SSH 协议",
     },
   },
   topology: {