When a host->candidate edge already exists from a prior chat, the
Add-guest form renders the prose textarea disabled with an "already
know each other" note. Submission without the explicit "re-seed
anyway" toggle skips seed_inter_bot_edges so existing edge content
(affinity, trust, knowledge, summaries) survives — guest_added and
group_node_initialized still fire. A small inline script enables /
disables the textarea per-option based on a pre-computed
existing_guest_edges dict surfaced by the GET handler.
Joseph Doherty