Add foundational components and logic for migration, UI design, and input handling

- Introduced foundational UI components (`Badge`, `LockCard`, `SectionHeader`, `AvatarIcon`, etc.) for flexible layouts and consistent design.
- Added migration support with the `MigrationModal` component and backend integration for exporting/importing data between Electron and Tauri.
- Extended form components with `TextAreaInput`, `OrderInput`, `ToggleField`, and `ToolbarSelect` for improved input handling.
- Updated `ScribeShell` with migration popup logic to prompt users for data migration.
- Integrated `AlertStack` for better alert handling and notification management.
- Enhanced Rust/Tauri services with migration command implementations.
- Added translations and styles for new components.

electron/main.ts

@@ -450,6 +450,79 @@ ipcMain.on('logout', ():void => {
   createLoginWindow();
 });
 
+// ========== MIGRATION EXPORT (Electron → Tauri) ==========
+
+ipcMain.handle('export-migration', async ():Promise<{success: boolean; path?: string; error?: string}> => {
+  const storage:SecureStorage = getSecureStorage();
+  const userId:string | null = storage.get<string>('userId', null);
+  const lastUserId:string | null = storage.get<string>('lastUserId', null);
+
+  const targetUserId:string | null = userId || lastUserId;
+  if (!targetUserId) {
+    return { success: false, error: 'No user found in storage' };
+  }
+
+  let encryptionKey:string | null = null;
+  try {
+    encryptionKey = getUserEncryptionKey(targetUserId);
+  } catch {
+    return { success: false, error: 'Encryption key not found for this user' };
+  }
+
+  const pinHash:string | null = storage.get<string>(`pin-${targetUserId}`, null);
+
+  const userDataPath:string = app.getPath('userData');
+  const dbPath:string = path.join(userDataPath, 'eritors-local.db');
+
+  if (!fs.existsSync(dbPath)) {
+    return { success: false, error: 'No local database found' };
+  }
+
+  const { filePath } = await dialog.showSaveDialog({
+    title: 'Export migration data',
+    defaultPath: path.join(app.getPath('desktop'), 'eritors-migration.json'),
+    filters: [{ name: 'Migration', extensions: ['json'] }],
+  });
+
+  if (!filePath) {
+    return { success: false, error: 'Export cancelled' };
+  }
+
+  const migrationData = {
+    version: 1,
+    exported_at: Date.now(),
+    user_id: targetUserId,
+    encryption_key: encryptionKey,
+    pin_hash: pinHash,
+    db_source: dbPath,
+  };
+
+  try {
+    fs.writeFileSync(filePath, JSON.stringify(migrationData, null, 2), 'utf-8');
+
+    // Copier aussi la DB à côté du fichier de migration
+    const dbDestination:string = path.join(path.dirname(filePath), `eritors-local-${targetUserId}.db`);
+    fs.copyFileSync(dbPath, dbDestination);
+
+    // Copier WAL et SHM si existants
+    const walPath:string = dbPath + '-wal';
+    const shmPath:string = dbPath + '-shm';
+    if (fs.existsSync(walPath)) {
+      fs.copyFileSync(walPath, dbDestination + '-wal');
+    }
+    if (fs.existsSync(shmPath)) {
+      fs.copyFileSync(shmPath, dbDestination + '-shm');
+    }
+
+    return { success: true, path: filePath };
+  } catch (error) {
+    return {
+      success: false,
+      error: error instanceof Error ? error.message : 'Export failed',
+    };
+  }
+});
+
 // ========== USER SYNC (PRE-AUTHENTICATION) ==========
 
 interface SyncUserData {