[Bug]: SSH connection silently downloads remote runtime and reports download failures as "host did not respond" #29253

Before submitting

• I searched existing issues and did not find a duplicate.
• I included enough detail to reproduce or investigate the problem.

Area

apps/desktop

Problem

Connecting to an existing SSH environment triggers a remote runtime download without showing that installation is taking place. When the download is slow or fails, the UI reports that the host did not respond during connection setup.

This sends users toward debugging SSH, network connectivity, or whether T3 is running, even though the logged failure is a download performed after SSH connects. I did not click the manual update button.

Steps to reproduce

1. Use desktop 0.1.6 with an existing SSH environment whose selected 0.1.6 runtime is not installed.
2. Have a slow or failing connection from the remote host to the release download service.
3. Connect or retry the SSH environment.
4. Observe the connection status and eventual error.

This describes the observed conditions; a controlled throttled reproduction has not been performed.

Actual behavior

The UI shows:

Cause: timeout
App version: 0.1.6
Host version: 0.1.5
Error: macmini did not respond during connection setup.

Desktop logs show the SSH launch selecting archive version 0.1.6, followed by:

curl: (28) SSL connection timeout

curl: (28) Operation timed out after 240003 milliseconds with 522728 out of 109830529 bytes received

Inspection of the installed app's launcher shows that it resolves/downloads the selected runtime before checking whether it can reuse an existing server. Failed attempts remove the staging directory, and subsequent attempts download from scratch.

Expected behavior

• Show an explicit "Installing/downloading remote runtime 0.1.6" status during connection setup.
• Surface download failures as download failures, preserving the underlying cause.
• Explain when a runtime installation is required despite an existing host installation and no explicit update request.
• If using the existing server is possible, avoid blocking that connection on a new runtime download.

Byte-level progress and resumable downloads would also help, but the core bug is that an installation failure is hidden behind a misleading connectivity error.

Impact

Blocks work completely

Version or commit

Desktop 0.1.6; UI reports host 0.1.5.

Environment

macOS desktop connecting to a Mac over SSH/Tailscale; both devices also share a LAN.

Related

#18113 covers progress, download timeouts, and discarded downloads in the separate server self-update path.