Add user data synchronization and database IPC handlers

- Introduce `db:user:sync` to synchronize user data with the local database during initialization.
- Add `db:user:info` and `db:user:update` IPC handlers for fetching and updating user information.
- Update `User` model and repository to support extended user fields and improved structure.
- Dynamically import user models in main process to avoid circular dependencies.
- Refactor database initialization in the app to include user sync logic with error handling.

app/page.tsx

@@ -226,7 +226,21 @@ function ScribeContent() {
                         const dbInitialized = await initializeDatabase(user.id);
                         if (dbInitialized) {
                             console.log('Database initialized successfully');
-                            // TODO: Sync initial des données du serveur vers la DB locale
+
+                            // Sync user to local DB (only if not exists)
+                            try {
+                                await window.electron.invoke('db:user:sync', {
+                                    userId: user.id,
+                                    firstName: user.name,
+                                    lastName: user.lastName,
+                                    username: user.username,
+                                    email: user.email
+                                });
+                                console.log('User synced to local DB');
+                            } catch (syncError) {
+                                console.error('Failed to sync user to local DB:', syncError);
+                                // Non-blocking error, continue anyway
+                            }
                         }
                     } catch (error) {
                         console.error('Failed to initialize database:', error);