Add engagement-only conversation mode

docs/frontend.md

@@ -82,6 +82,8 @@ The composer also has a separate green-screen creation panel. Its source picker
 
 The conversation inbox assigns every row to exactly one primary workflow queue: **Needs attention**, **Waiting**, **Sellers**, **Snoozed**, **Done**, **Deleted**, or **Archived**. Removed-account history belongs only to Archived, deleted recipients belong only to Deleted, and seller/off-platform outcomes belong only to Sellers, so none can leak into actionable work. Unread state, manual ownership, and received images are independent badges and secondary toggles rather than competing queues. The default queue is Needs attention. Suspended profiles are not treated as deleted.
 
+Subreddit conversation controls include an engagement-only policy. Its copy makes the boundary explicit: the normal opener is sent, the first reply completes the goal, and the bot does not answer it. Completed engagement conversations appear in Done and are not labelled as manual handoffs.
+
 ## Feature structure
 
 Each route is a slice under `features/<name>/` with page/route components, local styles, and feature-specific helpers. Cross-feature visual/domain components live under `components/`; application lifecycle belongs under `app/`; transport belongs under `api/`.