Add logic to download button in main window

src/ui/main_window.py

@@ -565,7 +565,15 @@ class MainWindow(QMainWindow):
             self.fetch_jobs(clear_table=True)
 
     def download_files(self, event):
-        pass
+
+        job_ids = self.selected_job_ids()
+        if not job_ids:
+            return
+
+        import webbrowser
+        download_url = (f"http://{self.current_server_proxy.hostname}:{self.current_server_proxy.port}"
+                        f"/api/job/{job_ids[0]}/download_all")
+        webbrowser.open(download_url)
 
     def open_files(self, event):
         job_ids = self.selected_job_ids()