Add retry extraction context menu, increase error text limit

- Right-click packages with extraction errors shows "Extraktion
  wiederholen" option to manually retry
- Increase WinRAR error text from 240 to 500 chars for better
  diagnostics in logs

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main/app-controller.ts

@@ -208,6 +208,10 @@ export class AppController {
     return this.manager.togglePause();
   }
 
+  public retryExtraction(packageId: string): void {
+    this.manager.retryExtraction(packageId);
+  }
+
   public cancelPackage(packageId: string): void {
     this.manager.cancelPackage(packageId);
   }