fix: clarify shadow refresh recovery contract

ruoyi-admin/src/test/java/com/ruoyi/algorithm/shadow/ShadowSnapshotCoordinatorTest.java

@@ -4,6 +4,8 @@ import org.junit.jupiter.api.Test;
 
 import java.time.Duration;
 import java.time.Instant;
+import java.time.ZoneOffset;
+import java.time.Clock;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -75,9 +77,31 @@ class ShadowSnapshotCoordinatorTest {
         ShadowSnapshotCoordinator.Admission wrongWarehouse = coordinator.enter(NOW);
         assertThat(wrongWarehouse.accepted()).isFalse();
         assertThat(wrongWarehouse.skipReason()).isEqualTo(ShadowSkipReason.WAREHOUSE);
+        assertThat(coordinator.phase()).isEqualTo(ShadowSnapshotCoordinator.Phase.BUSY);
         coordinator.exit(wrongWarehouse);
     }
 
+    @Test
+    void staleOrMismatchedEntryRecoversThroughRefresh() {
+        ShadowSnapshotCoordinator coordinator = coordinatorAt("01");
+        publish(coordinator, snapshot(7, "02", NOW));
+
+        ShadowSnapshotCoordinator.Admission skipped = coordinator.enter(NOW);
+        coordinator.exit(skipped);
+        assertThat(coordinator.phase()).isEqualTo(ShadowSnapshotCoordinator.Phase.BUSY);
+        assertThat(coordinator.tryBeginRefresh(NOW)).isPresent();
+    }
+
+    @Test
+    void exitUsesInjectedClockForQuietSince() {
+        Instant exitTime = NOW.plusSeconds(17);
+        ShadowSnapshotCoordinator coordinator = new ShadowSnapshotCoordinator(
+                "01", Duration.ofSeconds(60), Clock.fixed(exitTime, ZoneOffset.UTC));
+        ShadowSnapshotCoordinator.Admission admission = coordinator.enter(NOW);
+        coordinator.exit(admission);
+        assertThat(coordinator.quietSince()).isEqualTo(exitTime);
+    }
+
     @Test
     void treatsNumericWarehouseIdsAsEquivalent() {
         ShadowSnapshotCoordinator coordinator = coordinatorAt("01");