fix(tests): drop cross-module test-jar dep, copy helper locally

The previous commit added <type>test-jar</type> dependencies on
tarantool-core in client and jackson-mapping pom.xml. The maven-jar-plugin
only produces the test-jar artifact during the `package` phase, which
`mvn test` (used by CI's unit profile) does not reach. Downstream modules
therefore fail with "Could not find artifact ... in central-portal-snapshots".

Replace the cross-module test-jar deps with a copy of TimerShutdownHook
in each of the four modules' own test sources (the same pattern already
used for tarantool-schema in the previous commit). This matches the plan's
"Option A" recommendation that was originally only applied to schema.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: dkasimovskiy

tarantool-client/pom.xml

@@ -25,13 +25,6 @@
       <groupId>io.tarantool</groupId>
       <artifactId>tarantool-core</artifactId>
     </dependency>
-    <dependency>
-      <groupId>io.tarantool</groupId>
-      <artifactId>tarantool-core</artifactId>
-      <version>${project.version}</version>
-      <type>test-jar</type>
-      <scope>test</scope>
-    </dependency>
     <dependency>
       <groupId>io.tarantool</groupId>
       <artifactId>tarantool-jackson-mapping</artifactId>

tarantool-client/src/test/java/io/tarantool/client/integration/TarantoolCrudClientWithRetryTest.java

@@ -33,7 +33,6 @@
 import io.tarantool.client.crud.TarantoolCrudSpace;
 import io.tarantool.client.factory.TarantoolFactory;
 import io.tarantool.core.exceptions.BoxError;
-import io.tarantool.core.integration.TimerShutdownHook;
 import io.tarantool.mapping.Tuple;
 
 @Timeout(value = 5)

tarantool-client/src/test/java/io/tarantool/client/integration/TimerShutdownHook.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2026 VK DIGITAL TECHNOLOGIES LIMITED LIABILITY COMPANY
+ * All Rights Reserved.
+ */
+
+package io.tarantool.client.integration;
+
+import java.util.Set;
+import java.util.function.Supplier;
+
+import io.netty.util.Timeout;
+import io.netty.util.Timer;
+
+public final class TimerShutdownHook {
+  private TimerShutdownHook() {}
+
+  public static void register(Supplier<Timer> timerRef, String name) {
+    Runtime.getRuntime()
+        .addShutdownHook(
+            new Thread(
+                () -> {
+                  Timer t = timerRef.get();
+                  if (t != null) {
+                    Set<Timeout> pending = t.stop();
+                    if (pending != null) pending.forEach(Timeout::cancel);
+                  }
+                },
+                name));
+  }
+}

tarantool-jackson-mapping/pom.xml

@@ -25,13 +25,6 @@
       <groupId>io.tarantool</groupId>
       <artifactId>tarantool-core</artifactId>
     </dependency>
-    <dependency>
-      <groupId>io.tarantool</groupId>
-      <artifactId>tarantool-core</artifactId>
-      <version>${project.version}</version>
-      <type>test-jar</type>
-      <scope>test</scope>
-    </dependency>
     <dependency>
       <groupId>org.msgpack</groupId>
       <artifactId>jackson-dataformat-msgpack</artifactId>

tarantool-jackson-mapping/src/test/java/io/tarantool/mapping/integration/BaseTest.java

@@ -17,7 +17,6 @@
 import io.netty.util.Timer;
 
 import io.tarantool.core.connection.ConnectionFactory;
-import io.tarantool.core.integration.TimerShutdownHook;
 
 public abstract class BaseTest {
 

tarantool-jackson-mapping/src/test/java/io/tarantool/mapping/integration/TimerShutdownHook.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2026 VK DIGITAL TECHNOLOGIES LIMITED LIABILITY COMPANY
+ * All Rights Reserved.
+ */
+
+package io.tarantool.mapping.integration;
+
+import java.util.Set;
+import java.util.function.Supplier;
+
+import io.netty.util.Timeout;
+import io.netty.util.Timer;
+
+public final class TimerShutdownHook {
+  private TimerShutdownHook() {}
+
+  public static void register(Supplier<Timer> timerRef, String name) {
+    Runtime.getRuntime()
+        .addShutdownHook(
+            new Thread(
+                () -> {
+                  Timer t = timerRef.get();
+                  if (t != null) {
+                    Set<Timeout> pending = t.stop();
+                    if (pending != null) pending.forEach(Timeout::cancel);
+                  }
+                },
+                name));
+  }
+}