fix: grant account upsert read columns

frontend/supabase/migrations/20260718080000_profiles_service_role_account_upsert_selects.sql

@@ -0,0 +1,9 @@
+begin;
+
+-- Existing-row upserts must read every submitted column to resolve the result.
+grant select (
+  district_code,
+  updated_at
+) on table public.profiles to service_role;
+
+commit;