Review of #78: the once-per-session hold applied to anything classified
frame_unreachable, so after one status-poll timeout a web-link download whose
connection reset ("download failed: ... Connection reset by peer") lost its
$exception. Now the hold needs ssh's own wording (connect to host, could not
resolve, timed out talking to, banner exchange, mux/client_loop, connection
closed/reset by HOST port N); everything else keeps the 10-minute window.
Web-link download failures are download_failed. A bare "ssh exited 255" is
no longer frame_unreachable: the command on the Frame may have exited 255.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
