Archived
Replace the composer-local "Sending…" indicator with a single, consistent state surfaced by the existing chat activity dock. The session controller now owns the full attachment send lifecycle (including the folder-mode upload + reference rewrite) and toggles an isSendingPrompt flag around it, which the chat dock renders as "Sending your message…" until the real server activity supersedes it. This covers the pre-receipt dead zone (upload, server-side image resize, first-session open) with one indicator instead of two, and keeps plain text sends fire-and-forget.