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.

electron/ipc/user.ipc.ts

@@ -0,0 +1,26 @@
+import { ipcMain } from 'electron';
+import { createHandler } from '../database/LocalSystem.js';
+import User, {UserInfoResponse} from '../database/models/User.js';
+
+interface UpdateUserData {
+    firstName: string;
+    lastName: string;
+    username: string;
+    email: string;
+    authorName?: string;
+}
+
+// GET /user/info - Get user info from local DB
+ipcMain.handle('db:user:info', createHandler<void, UserInfoResponse>(
+    async function(userId: string, _body: void, _lang: 'fr' | 'en'):Promise<UserInfoResponse> {
+        return await User.returnUserInfos(userId);
+    }
+));
+
+// PUT /user/update - Update user info in local DB
+ipcMain.handle('db:user:update', createHandler<UpdateUserData, boolean>(
+    async function(userId: string, data: UpdateUserData, lang: 'fr' | 'en'):Promise<boolean> {
+        const userKey = '';
+        return await User.updateUserInfos(userKey, userId, data.firstName, data.lastName, data.username, data.email, data.authorName, lang);
+    }
+));