增强 SSH/SFTP 稳定性并完善安全校验与前端交互

backend/src/main/java/com/sshmanager/config/DataInitializer.java

@@ -6,6 +6,8 @@ import org.springframework.boot.CommandLineRunner;
 import org.springframework.security.crypto.password.PasswordEncoder;
 import org.springframework.stereotype.Component;
 
+import java.time.Instant;
+
 @Component
 public class DataInitializer implements CommandLineRunner {
 
@@ -24,6 +26,7 @@ public class DataInitializer implements CommandLineRunner {
             admin.setUsername("admin");
             admin.setPasswordHash(passwordEncoder.encode("admin123"));
             admin.setDisplayName("Administrator");
+            admin.setPasswordChangedAt(Instant.now());
             userRepository.save(admin);
         }
     }