fix(account): configure JDBC connection pool size to prevent exhaustion under load

Default Agroal pool (max-size=20) exhausted under concurrent logins due to
bcrypt latency per request. Fixes NCS-87.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

modules/account/src/main/resources/application.yml

@@ -76,6 +76,9 @@ nowchess:
       password: ${DB_PASSWORD}
       jdbc:
         url: ${DB_URL}
+        min-size: 10
+        max-size: 50
+        acquisition-timeout: 30
     hibernate-orm:
       schema-management:
         strategy: update