Fix SSH connections to another user account on the same Mac

[maddada]

Problem

SSH from Ghostex fails when connecting to another user account on the same Mac, even though the equivalent SSH connection works from a regular terminal. This prevents projects owned by the other macOS user from being opened directly through Ghostex.

Reproduction scenario

1. On a Mac with multiple user accounts, open Ghostex under one account.
2. Attempt to SSH to the same Mac using another account's username.
3. Compare with the equivalent SSH command in a regular terminal.
4. The regular terminal connection succeeds, while the Ghostex connection does not.

Expected behavior

Ghostex should support the same valid SSH destination and authentication configuration as the user's regular terminal, including connecting to another account on the same host.

Acceptance criteria

• A user can SSH through Ghostex to another macOS account on the same Mac when the equivalent terminal command succeeds.
• Connection errors are surfaced clearly enough to diagnose authentication or configuration problems.
• After connecting, the user can access and open projects belonging to the remote account.

Investigation notes

Compare Ghostex's SSH command construction, environment, identity/config loading, host resolution, and error reporting with the working terminal invocation.

Source

Reported via user feedback; exact SSH command and Ghostex error output may need to be collected during investigation.