Code cleanup, make sure race conditions can't happen, at least in theory.

src/fenrirscreenreader/soundDriver/gstreamerDriver.py

@@ -57,6 +57,9 @@ class driver(soundDriver):
             return
         self.cancel()
         self.mainloop.quit()
+        # Wait for the GLib MainLoop thread to finish to prevent shutdown races
+        if hasattr(self, 'thread') and self.thread.is_alive():
+            self.thread.join(timeout=2.0)  # 2 second timeout to prevent hanging
 
     def _onPlayerMessage(self, bus, message):
         if not self._initialized: