CB-562: log why the readiness gate gave up on a target

bridged/src/main/java/dev/ltms/bridged/inject/Injector.java

@@ -78,6 +78,13 @@ public final class Injector {
      */
     private static final int READINESS_GRACE_POLLS = 240;
 
+    /**
+     * The cadence the poller drives {@link #onStatus} at, matched to {@code Bridged.INJECT_POLL_MILLIS}.
+     * This class holds no timing itself (it is driven by the poller), so this exists only to state
+     * the readiness grace in seconds on the CB-562 expiry log instead of hardcoding "60s".
+     */
+    private static final long POLL_INTERVAL_MILLIS = 250;
+
     private final AgentControl agents;
     private final TurnListener turnListener;
     private final Predicate<String> ready; // CB-113: a target is deliverable only when available
@@ -264,6 +271,11 @@ public final class Injector {
                             // fail every queued message and release the target (CB-114) instead of
                             // polling it indefinitely with the caller's future never completing.
                             notReady = new ArrayList<>(t.queue);
+                            log.warn("readiness grace for {} expired after {} polls ({}s): target never "
+                                    + "became deliverable, so failing {} queued message(s) that never "
+                                    + "reached its pane",
+                                    target, READINESS_GRACE_POLLS,
+                                    READINESS_GRACE_POLLS * POLL_INTERVAL_MILLIS / 1000, notReady.size());
                             t.queue.clear();
                             t.notReadySincePoll = 0;
                         }

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

@@ -1,10 +1,15 @@
 package dev.ltms.bridged.inject;
 
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.LoggerContext;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
 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 org.junit.jupiter.api.Test;
+import org.slf4j.LoggerFactory;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -369,6 +374,39 @@ class InjectorTest {
         assertTrue(inj.activeTargets().isEmpty(), "the target is reclaimed, not polled forever");
     }
 
+    @Test
+    void readinessGraceExpiryIsLogged() {
+        // CB-562: the grace-expiry path used to clear the queue silently, so a message that never
+        // reached the worker's pane surfaced elsewhere as an unrelated turn-stall failure. Assert the
+        // expiry now names the real cause. (ListAppender capture pattern mirrors AuditLogTest.)
+        LoggerContext ctx = (LoggerContext) LoggerFactory.getILoggerFactory();
+        ch.qos.logback.classic.Logger injectorLog =
+                (ch.qos.logback.classic.Logger) LoggerFactory.getLogger(Injector.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.setContext(ctx);
+        appender.start();
+        injectorLog.addAppender(appender);
+        injectorLog.setLevel(Level.WARN);
+        try {
+            Injector inj = new Injector(new AgentControl(herdr), TurnListener.NOOP, _ -> false, _ -> {
+            });
+            inj.enqueue(T, "task");
+
+            for (int i = 0; i < READINESS_SAMPLES; i++) inj.onStatus(T, AgentStatus.IDLE);
+
+            String warn = appender.list.stream()
+                    .filter(e -> e.getLevel().equals(Level.WARN))
+                    .map(ILoggingEvent::getFormattedMessage)
+                    .findFirst()
+                    .orElse("no grace-expiry WARN logged");
+            assertTrue(warn.contains(T), "the log names the target terminal: " + warn);
+            assertTrue(warn.contains("never reached"), "the log names the real cause: " + warn);
+            assertTrue(warn.contains("1"), "the log carries the failed message count: " + warn);
+        } finally {
+            injectorLog.detachAppender(appender);
+        }
+    }
+
     @Test
     void aWorkerThatBecomesReadyWithinTheGraceIsDeliveredNormally() {
         // The readiness grace must not fail a worker that is merely slow to boot: once it becomes