Initial commit: SSH Manager (backend + frontend)

Co-authored-by: Cursor <cursoragent@cursor.com>

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

@@ -0,0 +1,30 @@
+package com.sshmanager.config;
+
+import com.sshmanager.entity.User;
+import com.sshmanager.repository.UserRepository;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.security.crypto.password.PasswordEncoder;
+import org.springframework.stereotype.Component;
+
+@Component
+public class DataInitializer implements CommandLineRunner {
+
+    private final UserRepository userRepository;
+    private final PasswordEncoder passwordEncoder;
+
+    public DataInitializer(UserRepository userRepository, PasswordEncoder passwordEncoder) {
+        this.userRepository = userRepository;
+        this.passwordEncoder = passwordEncoder;
+    }
+
+    @Override
+    public void run(String... args) {
+        if (userRepository.count() == 0) {
+            User admin = new User();
+            admin.setUsername("admin");
+            admin.setPasswordHash(passwordEncoder.encode("admin123"));
+            admin.setDisplayName("Administrator");
+            userRepository.save(admin);
+        }
+    }
+}