fix(ssh-remote): fallback SSH config parsing and fill-form UX - #1405

Summary

• Add manual ~/.ssh/config parsing fallback when the ssh_config crate fails (e.g. Include/Match directives before the first Host block), while still using pattern-matched query() results when parsing succeeds.
• Change SSH config host entries in the connection dialog to fill the manual form instead of connecting immediately, giving users a chance to review/edit credentials before connecting.

Test plan

• Verify ~/.ssh/config with Include/Match before first Host still lists hosts and resolves lookup correctly
• Verify wildcard Host * settings are applied when ssh_config parsing succeeds
• Click a config host entry and confirm the form is populated (host, port, user, key path)
• Connect via the filled form with both private key and password auth
• Confirm saved-connection credential prompt still works for missing stored secrets