Add is_archiver db helper function

supabase/migrations/20251130013154_add_archiver_role.sql

@@ -0,0 +1,12 @@
+CREATE OR REPLACE FUNCTION public.is_archiver()
+ RETURNS boolean
+ LANGUAGE sql
+ STABLE
+AS $function$
+  select 
+  	coalesce(get_my_claim('archiver')::bool,false)
+  	or
+  	coalesce(get_my_claim('claims_admin')::bool,false)
+$function$
+;
+