Fix test dependencies for MockWebServer

  - Add JUnit 4 dependency for MockWebServer compatibility
  - Use mockwebserver-version variable instead of okhttp-version

  🤖 Generated with [Claude Code](https://claude.com/claude-code)

  Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Leeon-Tang

pom.xml

@@ -357,7 +357,13 @@
         <dependency>
             <groupId>com.squareup.okhttp3</groupId>
             <artifactId>mockwebserver</artifactId>
-            <version>${okhttp-version}</version>
+            <version>${mockwebserver-version}</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.2</version>
             <scope>test</scope>
         </dependency>
         <dependency>