Implement enhanced login functionality with JWT, role-based permissions, and frontend integration

Added JWT-based login dialog with form validation and secure token handling on the frontend. Updated backend with role-based access control, privilege management, and refined security configurations. Extended database schema for user privileges and permissions.

backend/src/main/java/com/alttd/altitudeweb/services/user/UserDetailsServiceImpl.java

@@ -0,0 +1,27 @@
+package com.alttd.altitudeweb.services.user;
+
+import lombok.RequiredArgsConstructor;
+import org.springframework.security.core.userdetails.User;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.core.userdetails.UserDetailsService;
+import org.springframework.security.core.userdetails.UsernameNotFoundException;
+import org.springframework.stereotype.Service;
+
+import java.util.Collections;
+import java.util.UUID;
+
+@Service
+@RequiredArgsConstructor
+public class UserDetailsServiceImpl implements UserDetailsService {
+
+    @Override
+    public UserDetails loadUserByUsername(String uuid) throws UsernameNotFoundException {
+        try {
+            //Validate uuid
+            UUID.fromString(uuid);
+            return new User(uuid, "", Collections.emptyList());
+        } catch (IllegalArgumentException e) {
+            throw new UsernameNotFoundException("Invalid UUID format: " + uuid);
+        }
+    }
+}