Refactor: Fix notification view security

supabase/migrations/20251103002926_c819d1c0-be27-4811-8587-5cbfee979bc5.sql

@@ -0,0 +1,14 @@
+-- Add helper function for cleanup edge function
+
+CREATE OR REPLACE FUNCTION public.get_orphaned_edit_history()
+RETURNS TABLE (id UUID) AS $$
+BEGIN
+  RETURN QUERY
+  SELECT ieh.id
+  FROM item_edit_history ieh
+  WHERE NOT EXISTS (
+    SELECT 1 FROM submission_items si
+    WHERE si.id = ieh.item_id
+  );
+END;
+$$ LANGUAGE plpgsql SECURITY DEFINER SET search_path = public;