SSH agent: show full command line in approval dialog

The SSH agent approval dialog currently shows only the process name (e.g., “ssh”) when asking to approve key access. This isn’t very helpful - you can’t tell if it’s ssh git@github.com or ssh root@production-server.

The agent already has the PID from peer_cred() and could get the full command line via sysinfo’s process.cmd() in get_peer_info().

Showing the PID and/or full command (or at least the target host) in the approval dialog would make it much easier to decide whether to approve.

Current: ssh wants to use your key “my-key”
Better: [8831] ssh git@github.com wants to use your key “my-key”