bugfix empty string bypass in account_limits view

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: ryansmith3136

fe/src/schema.sql

@@ -100,7 +100,8 @@ create view account_limits as
     with current_plans as (
         select distinct on (owner_email) owner_email, rate, timeout, connections, queries
         from plan_changes
-        where (daimo_tx is not null or stripe_customer is not null)
+        where (daimo_tx is not null and daimo_tx != '')
+           or (stripe_customer is not null and stripe_customer != '')
         order by owner_email, created_at desc
     )
     select