fa93173b1f
Replies (messages with parentInteractionId) now open in a right-hand ThreadPane instead of inline quoting: - extracted a shared Composer (draft + @mention autocomplete + attach) and MessageItem (bubble + mentions + attachment + reactions + reply affordance) - Thread shows top-level messages only; a message with replies gets a '💬 N replies' link, and hovering shows 💬 'Reply in thread' - ThreadPane renders the root + its replies + a composer that posts back with parentInteractionId; Messenger becomes 3-column (list | thread | pane), pane closes on conversation switch - no contract/adapter/backend change (parentInteractionId was already wired) - thread-pane render test (open → reply → parent shows the count); 58 green Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>