viz: simplify SSH tunnel help, show user@host format

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: sbryngelson

toolchain/mfc/viz/interactive.py

@@ -726,19 +726,11 @@ def _tf(arr): return arr
     if host in ('127.0.0.1', 'localhost'):
         cons.print(
             f'\n[dim]To view from your laptop/desktop, open a [bold]new terminal on your local machine[/bold] and run:[/dim]\n'
-            f'\n  [bold]ssh -L {port}:localhost:{port} <host>[/bold]\n'
-            f'\n[dim]  Replace [bold]<host>[/bold] with whatever you normally pass to [bold]ssh[/bold] to reach this cluster.[/dim]\n'
-            f'[dim]  This can be a full hostname (e.g. [bold]login-phoenix.pace.gatech.edu[/bold])[/dim]\n'
-            f'[dim]  or an alias from your [bold]~/.ssh/config[/bold] (e.g. [bold]ssh -L {port}:localhost:{port} delta[/bold]).[/dim]\n'
-            f'[dim]  Then open [bold]http://localhost:{port}[/bold] in your local browser.[/dim]\n'
-            f'\n[dim]  [bold]2FA clusters:[/bold] if your cluster requires two-factor auth and you don\'t[/dim]\n'
-            f'[dim]  want to authenticate twice, add [bold]ControlMaster[/bold] to your [bold]~/.ssh/config[/bold]:[/dim]\n'
-            f'[dim]     Host <host>[/dim]\n'
-            f'[dim]       ControlMaster auto[/dim]\n'
-            f'[dim]       ControlPath ~/.ssh/sockets/%r@%h-%p[/dim]\n'
-            f'[dim]       ControlPersist 600[/dim]\n'
-            f'[dim]  Then your first SSH session handles 2FA; the tunnel reuses it.[/dim]\n'
-            f'[dim]  (Run [bold]mkdir -p ~/.ssh/sockets && chmod 700 ~/.ssh/sockets[/bold] once if the dir does not exist.)[/dim]'
+            f'\n  [bold]ssh -L {port}:localhost:{port} user@cluster-hostname[/bold]\n'
+            f'\n[dim]  Replace [bold]user@cluster-hostname[/bold] with whatever you normally pass to [bold]ssh[/bold][/dim]\n'
+            f'[dim]  to reach this cluster (e.g. [bold]jdoe@login.delta.ncsa.illinois.edu[/bold] or an[/dim]\n'
+            f'[dim]  alias from your [bold]~/.ssh/config[/bold]).[/dim]\n'
+            f'[dim]  Then open [bold]http://localhost:{port}[/bold] in your local browser.[/dim]'
         )
     cons.print('[dim]\nCtrl+C to stop.[/dim]\n')
     app.run(debug=False, port=port, host=host)