test: provide additional comments and guards for oauth test support

Author: joshuaNathaniel

api/src/main/java/io/kafbat/ui/config/auth/OAuthSecurityConfig.java

@@ -62,7 +62,8 @@ public class OAuthSecurityConfig extends AbstractAuthSecurityConfig {
   private final OAuthProperties properties;
 
   /**
-   * WebClient configured to use system proxy properties (-Dhttps.proxyHost, -Dhttps.proxyPort).
+   * WebClient configured to use system proxy properties (http.proxyHost/https.proxyHost,
+   * http.proxyPort/https.proxyPort, http.nonProxyHosts/https.nonProxyHosts).
    * Created as a bean to ensure system properties are read after context initialization.
    */
   @Bean(name = "oauthWebClient")

api/src/test/java/io/kafbat/ui/config/auth/OAuthTestSupport.java

@@ -96,6 +96,7 @@ public static synchronized void ensureStarted(boolean enableProxy) {
       initialized = true;
     }
 
+    // Intentionally outside the initialized block - different tests may toggle proxy on/off
     // Set or clear proxy system properties based on enableProxy
     if (enableProxy) {
       System.setProperty("http.proxyHost", "localhost");
@@ -132,7 +133,9 @@ public static void resetServers() {
     }
     if (proxyServer != null) {
       proxyServer.resetAll();
-      // Re-stub proxy forwarding after reset
+    }
+    // Re-stub proxy forwarding after reset
+    if (proxyServer != null && oauthServer != null) {
       proxyServer.stubFor(WireMock.any(urlMatching(".*"))
           .willReturn(aResponse().proxiedFrom("http://localhost:" + oauthServer.port())));
     }