fix(frontend): guard concurrent uploads and remove dead test in audio upload component

Add early return in onFileSelected when isUploading is true to prevent
race conditions from concurrent file selections. Remove the second spec
test that had a dead metadata variable and duplicated the first test's
assertion.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ELin2025

frontend/src/app/workspace/component/hugging-face-audio-upload/hugging-face-audio-upload.component.spec.ts

@@ -23,11 +23,4 @@ describe("HuggingFaceAudioUploadComponent (unit)", () => {
   it("should be defined", () => {
     expect(HuggingFaceAudioUploadComponent).toBeDefined();
   });
-
-  it("should have the correct selector", () => {
-    const metadata = Reflect.getOwnPropertyDescriptor(HuggingFaceAudioUploadComponent, "__annotations");
-    // Component decorator metadata is available via the Angular compiler;
-    // at minimum verify the class is importable and constructable metadata exists.
-    expect(HuggingFaceAudioUploadComponent.prototype).toBeDefined();
-  });
 });

frontend/src/app/workspace/component/hugging-face-audio-upload/hugging-face-audio-upload.component.ts

@@ -71,6 +71,9 @@ export class HuggingFaceAudioUploadComponent extends FieldType<FieldTypeConfig>
   }
 
   async onFileSelected(event: Event): Promise<void> {
+    if (this.isUploading) {
+      return;
+    }
     this.errorMessage = "";
     const input = event.target as HTMLInputElement;
     const file = input.files?.[0];