The sender column showed participants[0], and participants are rebuilt
newest message first — so replying to a thread put the user in that slot
and the list named them instead of the person who wrote in.
Thread summaries (list and search) now carry `senders`: the distinct From
addresses of the thread's visible messages, oldest first, with the same
Trash/Spam visibility as the message count. The list joins them and shows
the user's own account addresses as "me" ("me, Alice" for a thread the
user started), and the avatar prefers the other side of the conversation.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>