refacto for DAO folder and 4 tiers architecture

feat: ajout des fonctionnalités admin (changement visibilité salon, kick, gestion membres privés), contrôle d'accès salons privés, empêchement lecture/envoi pour kick, SSE long-polling pour instantanéité navigation/messages

added SSE to the project so the message refresh each time a user write a message

Refactor user handling by consolidating UserRepository methods into User class

Refactor chat view and styles for improved layout and user experience

Enhance form and salon views with improved styling and structure

Add button styles and update views for consistent UI (#3)

Add base and form CSS files; update login and register views for improved styling (#2)

Routes login control

first commit! yayy