review-003 doc items: S-1/N-1/N-2/N-3 — the accepted-residual posture notes

src/local/producer_door.rs

@@ -133,9 +133,12 @@ impl ProducerDoorBuilder {
         self
     }
 
-    /// The max-concurrent-sessions cap (ADR-014 knob 2): an accept
-    /// beyond the bound is refused door-side — the socket is closed
-    /// immediately, no session spawned.
+    /// The max-concurrent-*connections* cap (ADR-014 knob 2; review
+    /// 003 N-3's naming — the mechanism bounds accepted connections,
+    /// including ones past the idle gate that are merely slow
+    /// readers, not active RFC sessions): an accept beyond the bound
+    /// is refused door-side — the socket is closed immediately, no
+    /// session spawned.
     pub fn max_sessions(mut self, cap: usize) -> Self {
         self.max_sessions = Some(cap);
         self
@@ -191,6 +194,10 @@ impl ProducerDoorGuard {
     /// they own their sockets and finish with their clients (per-
     /// connection isolation cuts both ways). Returns the loop task's
     /// fatal outcome, if any (`None` = the loop ended by close).
+    ///
+    /// The receiver is dropped before the await — the loop's
+    /// `done_tx.closed()` fires only when every receiver is gone;
+    /// holding it across the await would deadlock the graceful stop.
     pub async fn close(mut self) -> Option<std::io::Error> {
         self.done_rx = None;
         let task = self.task.take();