feat(agent-loop): give each send its own turn

packages/ui/acp/src/index.ts

@@ -709,8 +709,8 @@ export function apply(ctx: Context, config: AcpConfig): void {
         // session/cancel maps to the queue-aware agent.cancel(reason): it aborts
         // a RUNNING step, clears the queued + steering FIFOs, and drops a
         // turn that is about to start (the pre-step window) — so a queued-but-
-        // not-yet-started prompt never runs, and a prompt accepted right after
-        // cannot be batched into the cancelled turn. Scoped to THIS session's
+        // not-yet-started prompt never runs, while a prompt accepted afterward
+        // remains a separate queued turn. Scoped to THIS session's
         // agent — a cancel in one session never touches another's stream or
         // pending prompt (RFC 011 isolation). We ALSO settle the in-flight prompt
         // as cancelled directly here: do NOT rely on the resulting turn/end to