- Forum parent channel IDs now match free-response list (add a forum
channel ID and all its threads respond without mention)
- Better thread chat names: 'Guild / forum / thread' for forum threads
- Add discord.require_mention and discord.free_response_channels to
config.yaml (bridged to env vars, env vars still override)
- Keep require_mention defaulting to true (safe for shared servers)
Cherry-picked from PR #867 by insecurejezza with default fix and
config.yaml integration.
Co-authored-by: insecurejezza <insecurejezza@users.noreply.github.com>