feat: Separate Gateway and Tool server architectures, implement Tool Auto-Registration, and add mock response mapping

src/main/java/io/shinhanlife/AxHubGatewayApplication.java

@@ -0,0 +1,22 @@
+package io.shinhanlife;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.ComponentScan;
+
+import java.util.Collections;
+
+@SpringBootApplication
+@ComponentScan(basePackages = {
+    "io.shinhanlife.axhub.biz.mcp.gateway", 
+    "io.shinhanlife.axhub.biz.mcp.adapter", 
+    "io.shinhanlife.axhub.common.mcp"
+})
+public class AxHubGatewayApplication {
+    public static void main(String[] args) {
+        SpringApplication app = new SpringApplication(AxHubGatewayApplication.class);
+        // Gateway는 8081 포트에서 실행
+        app.setDefaultProperties(Collections.singletonMap("server.port", "8081"));
+        app.run(args);
+    }
+}