Unanswered SSH password prompt pegs the UI thread at ~100% of a core

What happens

With a remote (SSH) workspace waiting on a password prompt (the zed --askpass helper alive), the Zed UI thread spins at ~100% of a core. Measured over a 20 s window with per-thread CPU sampling: 99.8% of one core on the main thread; the same build idles at ~2% when no prompt is pending.

Reproduction

1. Open a remote project over SSH with password auth (no key configured).
2. Leave the password prompt unanswered — keep using the local editor.
3. The main thread pegs (~100%), and the editor feels heavy for everything else.

Workaround

Killing the stuck ssh -N …ControlMaster=yes process and its zed --askpass child drops the UI thread immediately (99.8% → ~13% in our measurement; it does not respawn).

Notes

• Seen on 1.21.0, Linux/Wayland (also observed earlier on 1.20.1).
• Zed.log shows nothing recurring while it spins; it's userspace CPU on the main thread, not I/O.
• Happy to run more instrumentation (hang traces / stacks) if that would help.