Add basic column selection

src/app/app.component.ts

@@ -15,6 +15,8 @@ import { SplitButtonModule } from 'primeng/splitbutton';
 import { InputTextModule } from 'primeng/inputtext';
 import { FileTreeComponent } from './file-tree/file-tree.component';
 import { FileViewerComponent } from './file-viewer/file-viewer.component';
+import { ColumnEditorComponent } from './column-editor/column-editor.component';
+import { Column } from './duckdb.service';
 
 @Component({
   selector: 'app-root',
@@ -29,12 +31,14 @@ import { FileViewerComponent } from './file-viewer/file-viewer.component';
     SplitButtonModule,
     FileTreeComponent,
     FileViewerComponent,
+    ColumnEditorComponent,
   ],
   templateUrl: './app.component.html',
   styleUrl: './app.component.scss',
 })
 export class AppComponent {
   protected selectedFile = signal<File | undefined>(undefined);
+  protected selectedFileColumns = signal<Column[]>([]);
   protected tabs = signal<File[]>([]);
   protected selectedTab = signal(0);
   protected dragging = signal(false);