CB-110: fail an in-flight delegation when its worker vanishes

Companion to CB-109. When a worker disappears mid-turn (pane crash → herdr
*_not_found), the status poller drops the target, which failed only *queued*
messages — a message already DELIVERED is out of the queue, so its send's
rendezvous was left hanging until the 30-min async timeout. Injector.drop now
fires onTurnFailed for a delivered-but-unresolved turn (awaitingCompletion), so
the send resolves as WORKER_FAILED. Reuses the CB-109 resolver path; the failure
reason is neutral to cover both wedge (stuck) and vanish (gone).

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

@@ -239,6 +239,20 @@ class InjectorTest {
         assertTrue(f.isCompletedExceptionally(), "queued waiters unblock when the worker vanishes");
     }
 
+    @Test
+    void dropFailsTheTurnOfADeliveredMessageWhenTheWorkerVanishes() {
+        // CB-110: the message was delivered (no longer queued), so failing queued waiters alone would
+        // leave its send hanging. A vanished worker must fail that in-flight turn too.
+        Captor cap = new Captor();
+        Injector inj = new Injector(new AgentControl(herdr), cap);
+        inj.enqueue(T, "task");
+        inj.onStatus(T, AgentStatus.IDLE);    // deliver
+        inj.onStatus(T, AgentStatus.WORKING); // turn running
+
+        inj.drop(T, new HerdrException("worker gone", "pane_not_found", null));
+        assertEquals(List.of(T), cap.failed, "a worker that vanishes mid-turn fails its in-flight send");
+    }
+
     @Test
     void pollerDeliversToAnIdleWorker() throws Exception {
         // End-to-end through the poller: idle worker → message delivered without manual onStatus.

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

@@ -3,6 +3,7 @@ package dev.ltms.bridged.msg;
 import dev.ltms.bridged.herdr.AgentControl;
 import dev.ltms.bridged.herdr.AgentStatus;
 import dev.ltms.bridged.herdr.FakeHerdr;
+import dev.ltms.bridged.herdr.HerdrException;
 import dev.ltms.bridged.inject.CompletionResolver;
 import dev.ltms.bridged.inject.Injector;
 import org.junit.jupiter.api.Test;
@@ -88,4 +89,20 @@ class MessageServiceTest {
         assertFalse(reply.completed(), "a wedge is terminal but not a successful completion");
         assertTrue(reply.text().contains("ENOTFOUND"), "the error screen is carried as the failure reason");
     }
+
+    @Test
+    void aWorkerThatVanishesMidTurnResolvesTheSendAsFailed() throws Exception {
+        CompletableFuture<MessageService.Reply> send = sendAsync();
+        awaitWaiting();
+
+        injector.onStatus(T, AgentStatus.IDLE);    // deliver
+        injector.onStatus(T, AgentStatus.WORKING); // worker starts the turn
+        // The worker's pane crashes — the poller sees a *_not_found and drops it (CB-110).
+        injector.drop(T, new HerdrException("worker gone", "pane_not_found", null));
+
+        MessageService.Reply reply = send.get(5, TimeUnit.SECONDS);
+        assertEquals(MessageService.Outcome.WORKER_FAILED, reply.outcome(),
+                "a delivered send whose worker vanishes fails instead of hanging to the timeout");
+        assertFalse(reply.completed());
+    }
 }