fix: 권한 에러

Author: yongho9064

backend/src/main/java/com/ai/lawyer/global/security/SecurityConfig.java

@@ -57,6 +57,7 @@ public class SecurityConfig {
             "/api/law/**",            // 법령 (공개)
             "/api/law-word/**",       // 법률 용어 (공개)
             "/api/home/**",         // 홈 (공개)
+            "/api/chat/**",        // 챗봇
             "/h2-console/**",          // H2 콘솔 (개발용)
             "/actuator/health", "/actuator/health/**", "/actuator/info",    // Spring Actuator
             "/api/actuator/health", "/api/actuator/health/**", "/api/actuator/info",