fix: resolve customer creation fk violation and implement instant updates in admin dialogs

shop/supabase/migrations/20260623000000_add_profiles_trigger_and_backfill.sql

@@ -0,0 +1,19 @@
+-- Trigger, um Profile automatisch bei User-Erstellung in auth.users anzulegen
+CREATE OR REPLACE FUNCTION public.handle_new_user()
+RETURNS TRIGGER AS $$
+BEGIN
+  INSERT INTO public.profiles (id)
+  VALUES (new.id)
+  ON CONFLICT (id) DO NOTHING;
+  RETURN NEW;
+END;
+$$ LANGUAGE plpgsql SECURITY DEFINER;
+
+CREATE OR REPLACE TRIGGER on_auth_user_created
+  AFTER INSERT ON auth.users
+  FOR EACH ROW EXECUTE FUNCTION public.handle_new_user();
+
+-- Profile für bereits existierende Benutzer anlegen (Backfill)
+INSERT INTO public.profiles (id)
+SELECT id FROM auth.users
+ON CONFLICT (id) DO NOTHING;