T44 carried a defensive degrade-to-1:1 block in post_turn for the
case where chat.guest_bot_id pointed at a deleted bot. T47 then
fixed the root cause by adding a bot_reset cascade that clears
guest_bot_id from any chat that referenced the deleted bot, so the
post_turn defensive block was rendered dead.
Remove the orphan-clear branch and replace it with a comment
documenting that get_bot now returns a real row when guest_bot_id
is non-None. The cascade behavior is pinned by
test_reset_clears_guest_reference_in_other_chats in tests/test_reset.py.
Joseph Doherty
6d98728a2e