fleetd #551 shape sweep: fix stale ATTEMPTED-route javadoc/comments in MessageService

hasQueuedDelivery's javadoc, the queuedDeliveries field javadoc, and a code
comment in send()'s timeout path all still made two claims that ATTEMPTED
(fleetd #551) falsifies: a blanket "the message will not arrive later" across
every route, and "the terminal may already hold a partial paste" — but
agent.prompt pastes AND submits in one call, so the target may hold a
complete, already-submitted turn. Each now names the three Injector.Cancellation
routes (CANCELLED, NOT_DELIVERED, ATTEMPTED) and says plainly that only the
first two establish the message will not arrive later.

Comment/javadoc only. No behaviour change: Injector.java is untouched
(sha256 0c689b6cf36275c0da45497a74b2bd4f5a3d80c4dbda77d46670c66004e53b69) and
no test was added. mvn -o clean install: BUILD SUCCESS, Tests run: 1754,
Failures: 0, Errors: 0 (unchanged from before this commit).

fleetd/src/main/java/dev/ltms/fleet/msg/MessageService.java

@@ -319,16 +319,18 @@ public final class MessageService {
     /**
      * Targets whose last send timed out with {@link Outcome#TIMED_OUT_QUEUED} (CB-640) — {@link
      * #send} called {@link Injector#cancel} and got back something other than {@code DELIVERED}.
-     * That covers more than one history: the message may have still been queued and {@code cancel}
-     * removed it right there, or an earlier attempt may already have failed (the call to the
-     * target's terminal threw) or been abandoned (the target never became ready, or was torn
-     * down). What holds on every route: the message will not arrive later, and it is not sitting
-     * in any queue. What does NOT hold on every route: that the target saw nothing — a failed
-     * delivery attempt can leave a partial paste behind. Set where {@link #send} already computes
-     * {@code wasDelivered} for that outcome; no queue is kept here, only the fact that the send
-     * ended with no confirmed delivery. Cleared the same way as {@link #strandedReplies}: the next
-     * accepted delivery for the target ({@link #send} opening a fresh waiter) or a teardown
-     * ({@link #abandon}).
+     * That covers three histories, not one: {@link Injector.Cancellation#CANCELLED} — the message
+     * was still queued and {@code cancel} removed it right there; {@link
+     * Injector.Cancellation#NOT_DELIVERED} — nothing was ever sent, because the target never became
+     * ready, was torn down, or the call to its terminal failed with a herdr error this codebase
+     * already treats as a confirmed absence; or {@link Injector.Cancellation#ATTEMPTED} (fleetd
+     * #551) — the call to the target's terminal was made and its outcome is unknown, so the target
+     * may already hold a complete, submitted turn. Only the first two mean the message will not
+     * arrive later and the target saw nothing; on the third it may already have arrived in full.
+     * Set where {@link #send} already computes {@code wasDelivered} for that outcome; no queue is
+     * kept here, only the fact that the send ended with no confirmed delivery. Cleared the same way
+     * as {@link #strandedReplies}: the next accepted delivery for the target ({@link #send} opening
+     * a fresh waiter) or a teardown ({@link #abandon}).
      */
     private final ConcurrentHashMap<String, Boolean> queuedDeliveries = new ConcurrentHashMap<>();
     private final AtomicLong ticketSeq = new AtomicLong();
@@ -418,14 +420,18 @@ public final class MessageService {
      * with no confirmed delivery — the caller saw {@link Outcome#TIMED_OUT_QUEUED} (see the
      * {@code TimeoutException} branch of {@link #send}). Despite the method's name, this is not
      * proof that a message is sitting in a queue: {@link Injector#cancel} reports this outcome
-     * either because the message was still queued and got removed right there, or because an
-     * earlier attempt already failed (the call to the target's terminal threw) or was abandoned
-     * (the target never became ready, or was torn down). Either way the message will not arrive
-     * later. It does NOT follow that the target saw nothing — on the failed-attempt route the
-     * terminal may already hold a partial paste. Distinct from {@link Outcome#TIMED_OUT_WORKING},
-     * where delivery already happened and only the reply is outstanding. Cleared the next time
-     * this target's delivery is accepted or the target is abandoned — see
-     * {@link #queuedDeliveries}.
+     * through three routes. {@link Injector.Cancellation#CANCELLED} means the message was still
+     * queued and got removed right there. {@link Injector.Cancellation#NOT_DELIVERED} means
+     * nothing was ever sent — the target never became ready, was torn down, or the call to its
+     * terminal failed with a herdr error this codebase already treats as a confirmed absence.
+     * Only these two routes mean the message will not arrive later. {@link
+     * Injector.Cancellation#ATTEMPTED} (fleetd #551) means the call to the target's terminal was
+     * made and its outcome is unknown: {@code agent.prompt} pastes <em>and submits</em> in one
+     * call, so on this route the target may already hold a complete, submitted turn and be
+     * working on it right now — it does NOT follow that the target saw nothing. Distinct from
+     * {@link Outcome#TIMED_OUT_WORKING}, where delivery already happened and only the reply is
+     * outstanding. Cleared the next time this target's delivery is accepted or the target is
+     * abandoned — see {@link #queuedDeliveries}.
      */
     public boolean hasQueuedDelivery(String target) {
         return target != null && queuedDeliveries.containsKey(target);
@@ -980,11 +986,12 @@ public final class MessageService {
                     }
                     log.debug("send to {} timed out (delivered={})", target, wasDelivered);
                     if (!wasDelivered) {
-                        // CB-640: record that delivery did not happen for fleet health (see
+                        // CB-640: record that delivery is not confirmed, for fleet health (see
                         // queuedDeliveries). Whatever injector.cancel() reported above — this call
-                        // removed a still-queued Pending, or an earlier attempt already failed or
-                        // was abandoned — the send ends with no confirmed delivery and will not
-                        // arrive later.
+                        // removed a still-queued Pending (CANCELLED), an earlier attempt already
+                        // failed with a confirmed absence (NOT_DELIVERED), or an earlier attempt was
+                        // made and its outcome is unknown (ATTEMPTED, fleetd #551 — the message may
+                        // already have arrived in full) — the send ends with no confirmed delivery.
                         queuedDeliveries.put(target, Boolean.TRUE);
                     }
                     return recorded(new Reply(