add error reporting to download process

app/main.py

@@ -126,16 +126,29 @@ class DownloadVideo(ui.View):
 
         worker_task = asyncio.create_task(progress_worker(msg))
 
+        error = None
+
         async def progress_callback(percent):
             await progress_queue.put(percent)
         
-        await asyncio.to_thread(
-            ytdlp.download_video, self.url, format_string, out_path, temp_path, progress_callback, asyncio.get_event_loop()
-        )
+        loop = asyncio.get_running_loop()
+        def threaded_download():
+            nonlocal error
+            try:
+                ytdlp.download_video( 
+                    self.url, format_string, out_path, temp_path, progress_callback, loop
+                    )
+            except Exception as e:
+                error = e
+        await asyncio.to_thread(threaded_download)
 
         stop_event.set()
         await worker_task
 
+        if error:
+            await msg.edit(content=f"❌ Download failed: {error}")
+            return
+
         # Show completion and summary
         await msg.edit(content="✅ Download complete!\n"
         )