Fix relative import in signals causing broadcast failures

Changed relative import to absolute import in signals.py to prevent
"No module named 'schedule'" errors when broadcasting WebSocket events
from management commands.

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Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

smoothschedule/smoothschedule/scheduling/schedule/signals.py

@@ -45,7 +45,7 @@ def broadcast_event_change_sync(event, update_type, changed_fields=None, old_sta
         return
 
     try:
-        from .consumers import broadcast_event_update
+        from smoothschedule.scheduling.schedule.consumers import broadcast_event_update
         async_to_sync(broadcast_event_update)(
             event,
             update_type=update_type,