Face rooms: a plain line should let every Bot in the room answer (one round, capped), not only the first (follow-up to #287) #295

User feedback on #288: in a face room they typed plain lines ("你是干嘛的", "你们都是干嘛的") and only the first local Bot (技术文档) answered; they expected the others too (#288 chose one speaker, the admin else the first member).

New rule for a plain human line (no @ naming a Bot): one round in which every Bot in the room may answer, one at a time, each seeing the earlier replies, capped at 6 speakers (admin first, then room order), with no Bot-triggered follow-ups inside that round. Applies on both homes: the owner's own line on the sender's home, and a friend's line on the receiving home, but there only when the server attests it typed_by_owner (the friend's Bots start on a person's line, never on a Bot's). @Name still targets only that Bot; a Bot's own post still starts only the Bots it @-names (remote Bot posts start none), so two homes cannot set each other off. Approval/Auto-send gating of each Bot's outbound line is unchanged.