[Bug] Remote SSH connect always fails: "Handshake timeout: no zcode-hello received within timeout"

提交前确认 · Pre-submission checklist

• 我已搜索过现有 issue，确认这不是重复 / I searched existing issues and confirmed this isn't a duplicate.
• 我已阅读 CONTRIBUTING.md / I've read CONTRIBUTING.md.

问题类别 · Category

其他 / 不确定 · Other / Not sure

涉及的 Agent 框架 · Agent framework

ZCode Agent（自研）

严重程度 · Severity

阻塞使用 · Blocking (无法使用核心功能 / core function unusable)

复现频率 · Reproducibility

必现 · Always

问题描述 · Description

ZCode Desktop cannot connect to a remote host over SSH. The client gives the
remote server a fixed 10 seconds to print its first stdout line ("zcode-hello").
On a slow remote the server needs well over 10 s just to load its ~11.4 MB
bundle (measured on my setup: ~18 s steady-state, up to ~2.5 min under load),
so the handshake deterministically times out. The server itself is healthy:
"zcode-hello" is the very first thing it prints — it simply boots later than
the client is willing to wait. No stderr, no crash. The 10 s timeout is
hardcoded (default arg 1e4 ms, two copies in app.asar), with no setting or
env var to change it.

Possible fixes (either one works):

1. A user-facing setting for the remote handshake timeout;
2. A higher default value (e.g. 90 s instead of the current 10 s).

复现步骤 · Steps to reproduce

1. Prepare a slow remote host. For easy reproduction, run a Linux x64 VM under QEMU with software emulation (TCG), i.e. WITHOUT hardware acceleration, e.g.:
   qemu-system-x86_64 -accel tcg -smp 1 -m 2G
   -drive file=linux-x64.qcow2,if=virtio
   -nic user,hostfwd=tcp::2222-:22
   This is just a convenient way to get a slow CPU — any slow or heavily loaded remote host triggers the same failure.
2. In ZCode Desktop, open the remote connection dialog and connect to this host over SSH (fill in user / host / port in the UI).
3. Watch the connection progress: remote components deploy successfully, then the client switches to establishing the session.
4. About 10 seconds later the connection fails with the error message "Handshake timeout: no zcode-hello received within timeout". Retrying always gives the same result.

期望表现 · Expected behavior

The connection should succeed: the remote server does print "zcode-hello". Ideally the handshake timeout would be configurable via a user-facing setting, so slow-but-healthy remotes can connect.

实际表现 · Actual behavior

The connection always fails ~10 s after the deploy phase, before the remote server finishes loading. Remote SSH workspaces are completely unusable on such hosts.

ZCode 版本 · ZCode version

3.12.3

设备 / 系统 / 浏览器 · Device / OS / Browser

Mac Pro/ Mac OS

截图 / 录屏 / 日志 · Screenshots / Recordings / Logs

Start by examining the remote SSH connection and handshake entry point in the app.asar bundle, where the report identifies two copies of the hardcoded timeout. Reproduce with a slow remote host and confirm that increasing or exposing the timeout lets the server reach the zcode-hello handshake and complete the connection.