feat: ASCII banner + graceful shutdown hook for ServerGuardApplication

src/main/java/com/aluer/ServerGuardApplication.java

@@ -1,13 +1,32 @@
 package com.aluer;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.scheduling.annotation.EnableAsync;
 
 @SpringBootApplication
 @EnableAsync
 public class ServerGuardApplication {
+    private static final Logger logger = LoggerFactory.getLogger(ServerGuardApplication.class);
+    private static volatile ConfigurableApplicationContext context;
+
     public static void main(String[] args) {
-        SpringApplication.run(ServerGuardApplication.class, args);
+        context = SpringApplication.run(ServerGuardApplication.class, args);
+
+        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
+            logger.info("JVM shutdown hook triggered — closing application context");
+            if (context != null) {
+                context.close();
+            }
+        }, "serverguard-shutdown-hook"));
+
+        logger.info("Aluer ServerGuard is ready");
+    }
+
+    public static ConfigurableApplicationContext getContext() {
+        return context;
     }
 }