confirm_destructive() prompts on stderr and blocking-reads a y/n answer
via a single, non-looping fgets() call (not libedit) -- the mechanism
that makes a real Ctrl-C during the prompt return EINTR and be treated
as a decline (Requirement 9.9), same as an explicit "n" or EOF.
confirm_set_skip()/confirm_is_skip_set() add a session-scoped toggle
mirroring cmd_set's existing -e/+e style. Auto-skips when input is not
interactive, via a new xcetest_is_interactive() accessor over the
existing g_interactive global. Destructive-command enumeration and
per-command wiring (Requirement 9.5) is task 3.3, not this task.
Proven with a real fork+SIGINT test. 1297/1297 controller suite
passing (+7).
Task 2.1 of .kiro/specs/xce-test-cli-ux/tasks.md.
Requirements: 9.1, 9.2, 9.3, 9.4, 9.6, 9.7, 9.8, 9.9
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019jaMf9QEwpugH2W9KAuc7f
