Add --force/-f flag to domain commands

[kbens]

Summary

• Add --force/-f flag to all 8 domain commands that call _confirm_targets() (bounce, configure, flush, kill, purge, restart, start, stop)
• Skips the confirmation prompt, same behavior as skip_domain_confirm config setting
• Rename stop's existing --force/-f (kill processes) to --hard/-H to free the flag for consistent skip-confirm behavior
• Update tip text to mention --force

Test plan

• 17 new tests in tests/test_domain_force_flag.py
• All 46 domain confirm-related tests pass
• Tests cover: force skips prompt, force threads through all 8 commands, stop --hard still uses kill action, tip text mentions --force