Function create_room 

pub fn create_room(
    conn: &Connection,
    room_id: &str,
    kind: RoomKind,
    creator_user_id: i64,
    created_at: &str,
    is_encrypted: bool,
    join_rule: JoinRule,
    history_visibility: HistoryVisibility,
    dm_pair_key: Option<&str>,
    legacy_dm_id: Option<i64>,
) -> Result<()>

Insert a room’s metadata row only — no bootstrap state events (those go through apply_state_event separately, e.g. m.room.create, m.room.member, m.room.power_levels, per plan §5/§7). Kept as a standalone single-row entry point for a future non-transactional caller and for this module’s own tests; create_room_with_state is the P5 batch entry point everything under routes::matrix::rooms uses instead.