fix: Improve background thread management and error handling in update check

src/webdrop_bridge/ui/main_window.py

@@ -194,6 +194,7 @@ class MainWindow(QMainWindow):
         """
         super().__init__(parent)
         self.config = config
+        self._background_threads = []  # Keep references to background threads
 
         # Set window properties
         self.setWindowTitle(f"{config.app_name} v{config.app_version}")
@@ -482,19 +483,34 @@ class MainWindow(QMainWindow):
         Args:
             manager: UpdateManager instance
         """
-        # Create and start background thread
-        thread = QThread()
-        worker = UpdateCheckWorker(manager, self.config.app_version)
-        
-        # Connect signals
-        worker.update_available.connect(self._on_update_available)
-        worker.update_status.connect(self._on_update_status)
-        worker.finished.connect(thread.quit)
-        
-        # Start thread
-        worker.moveToThread(thread)
-        thread.started.connect(worker.run)
-        thread.start()
+        try:
+            # Create and start background thread
+            thread = QThread()
+            worker = UpdateCheckWorker(manager, self.config.app_version)
+            
+            # Connect signals
+            worker.update_available.connect(self._on_update_available)
+            worker.update_status.connect(self._on_update_status)
+            worker.finished.connect(thread.quit)
+            worker.finished.connect(worker.deleteLater)
+            thread.finished.connect(thread.deleteLater)
+            
+            # Keep reference to thread to prevent garbage collection
+            self._background_threads.append(thread)
+            
+            # Clean up finished threads from list
+            def cleanup_thread():
+                if thread in self._background_threads:
+                    self._background_threads.remove(thread)
+            
+            thread.finished.connect(cleanup_thread)
+            
+            # Start thread
+            worker.moveToThread(thread)
+            thread.started.connect(worker.run)
+            thread.start()
+        except Exception as e:
+            logger.error(f"Failed to start update check thread: {e}")
 
     def _on_update_status(self, status: str, emoji: str) -> None:
         """Handle update status changes.
@@ -682,11 +698,25 @@ class UpdateCheckWorker(QObject):
             # Notify checking status
             self.update_status.emit("Checking for updates", "🔄")
             
-            # Run async check
-            loop = asyncio.new_event_loop()
-            asyncio.set_event_loop(loop)
-            release = loop.run_until_complete(self.manager.check_for_updates())
-            loop.close()
+            try:
+                # Run async check with timeout
+                loop = asyncio.new_event_loop()
+                asyncio.set_event_loop(loop)
+                release = loop.run_until_complete(self.manager.check_for_updates())
+                loop.close()
+            except RuntimeError as e:
+                # Handle event loop already running or other asyncio issues
+                logger.warning(f"Asyncio error during update check: {e}")
+                # Try using existing loop
+                try:
+                    loop = asyncio.get_event_loop()
+                    if loop.is_closed():
+                        loop = asyncio.new_event_loop()
+                        asyncio.set_event_loop(loop)
+                    release = loop.run_until_complete(self.manager.check_for_updates())
+                except Exception as retry_error:
+                    logger.error(f"Failed to check updates on retry: {retry_error}")
+                    release = None
             
             # Emit result
             if release: