CB-568: preserve dropped turn causes

bridged/src/test/java/dev/ltms/bridged/inject/InjectorTest.java

@@ -259,6 +259,7 @@ class InjectorTest {
     private static final class Captor implements TurnListener {
         final List<String> completed = new ArrayList<>();
         final List<String> failed = new ArrayList<>();
+        final List<String> failureReasons = new ArrayList<>();
 
         @Override
         public void onTurnComplete(String target) {
@@ -269,6 +270,12 @@ class InjectorTest {
         public void onTurnFailed(String target) {
             failed.add(target);
         }
+
+        @Override
+        public void onTurnFailed(String target, String reason) {
+            failed.add(target);
+            failureReasons.add(reason);
+        }
     }
 
     // ~30s of unknown at the 250ms prod poll interval; enough onStatus samples to trip the stall.
@@ -322,6 +329,23 @@ class InjectorTest {
         assertTrue(f.isCompletedExceptionally(), "queued waiters unblock when the worker vanishes");
     }
 
+    @Test
+    void dropPassesTheRealCauseForQueuedAndDeliveredWork() {
+        Captor cap = new Captor();
+        Injector inj = new Injector(new AgentControl(herdr), cap);
+        CompletableFuture<Void> delivered = inj.enqueue(T, "delivered");
+        CompletableFuture<Void> queued = inj.enqueue(T, "queued");
+
+        inj.onStatus(T, AgentStatus.IDLE);    // deliver the first message
+        inj.onStatus(T, AgentStatus.WORKING); // its turn is now in flight; one remains queued
+        inj.drop(T, new HerdrException("agent target sol not found", "agent_not_found", null));
+
+        assertEquals(List.of(T), cap.failed, "drop signals one turn failure for both affected states");
+        assertEquals(List.of("agent target sol not found"), cap.failureReasons);
+        assertTrue(delivered.isDone(), "the delivered future has already completed");
+        assertTrue(queued.isCompletedExceptionally(), "the queued future fails with the drop cause");
+    }
+
     @Test
     void dropFailsTheTurnOfADeliveredMessageWhenTheWorkerVanishes() {
         // CB-110: the message was delivered (no longer queued), so failing queued waiters alone would

bridged/src/test/java/dev/ltms/bridged/msg/MessageServiceTest.java

@@ -120,6 +120,36 @@ class MessageServiceTest {
         assertFalse(reply.completed());
     }
 
+    @Test
+    void droppedQueuedAndDeliveredTurnsExposeTheRealCauseExactlyOnce() throws Exception {
+        CompletableFuture<MessageService.Reply> first = sendAsync();
+        awaitWaiting();
+        injector.onStatus(T, AgentStatus.IDLE);    // first delivery
+        injector.onStatus(T, AgentStatus.WORKING); // first turn in flight
+
+        CompletableFuture<Void> queued = injector.enqueue(T, "second task");
+        CompletableFuture<Rendezvous.Resolution> waiter = rendezvous.currentWaiter(T);
+        injector.drop(T, new HerdrException("agent target sol not found", "agent_not_found", null));
+
+        MessageService.Reply reply = first.get(5, TimeUnit.SECONDS);
+        assertEquals(MessageService.Outcome.WORKER_FAILED, reply.outcome());
+        assertEquals("agent target sol not found", reply.text());
+        assertTrue(queued.isCompletedExceptionally(), "the queued delivery future also fails");
+        assertFalse(rendezvous.resolveFailure(waiter, "second failure"), "the waiter fails exactly once");
+    }
+
+    @Test
+    void noDropReasonKeepsTheExistingFallbackText() throws Exception {
+        herdr.readText("");
+        CompletableFuture<Rendezvous.Resolution> waiter = rendezvous.open(T);
+
+        completion.onTurnFailed(T);
+
+        Rendezvous.Resolution resolution = waiter.get(2, TimeUnit.SECONDS);
+        assertEquals("worker did not reply; its turn ended in an unrecoverable state "
+                + "(worker unreachable or stuck)", resolution.text());
+    }
+
     // --- bridge_ask reverse rendezvous (CB-205) ------------------------------------------------
 
     @Test