Some legitimate @bot pings were dropped because the mention gates relied on
message.mentions alone, which does not always populate raw <@ID> / <@!ID>
forms (mobile, edited, relayed messages). A bare @bot with no other text
could also spawn a fake empty-text turn.
- add _self_is_explicitly_mentioned() / _raw_mentioned_user_ids() helpers that
treat the bot as mentioned via resolved mentions OR raw content forms
- use them at the allow_bots=mentions gate, multi-agent bot filtering, the
mention-strip/mention_prefix step, and the require_mention gate
- drop bare mention-only pings (no text, no media, no injection, no backfill
context) instead of injecting a placeholder empty turn
Co-authored-by: Teknium <teknium1@gmail.com>