refactor: improve stream cleanup before system reboot by closing WebRTC connections and stopping multicasters

src/auracast/server/multicast_server.py

@@ -594,11 +594,23 @@ async def system_reboot():
     Requires the service user to have passwordless sudo permissions to run 'reboot'.
     """
     try:
-        # Best-effort: stop any active streaming cleanly
+        # Best-effort: stop any active streaming cleanly WITHOUT persisting state
         try:
-            await stop_audio()
+            # Close any WebRTC peer connections
+            close_tasks = [pc.close() for pc in list(pcs)]
+            pcs.clear()
+            if close_tasks:
+                await asyncio.gather(*close_tasks, return_exceptions=True)
+
+            # Stop streaming on multicasters but DO NOT touch stream_settings.json
+            if multicaster1 is not None:
+                await multicaster1.stop_streaming()
+                await multicaster1.shutdown()
+            if multicaster2 is not None:
+                await multicaster2.stop_streaming()
+                await multicaster2.shutdown()
         except Exception:
-            log.warning("Failed to stop audio before reboot", exc_info=True)
+            log.warning("Non-fatal: failed to stop streams before reboot", exc_info=True)
 
         # Launch reboot without waiting for completion
         try: