Topics are declared rather than auto-created: the application account has no
Create ACL, so a producer would have been denied, and an auto-created topic
takes broker defaults nobody chose.
The credentials store lets an application namespace read its own KafkaUser
password and the cluster CA from the kafka namespace, so the password stays
generated and rotatable by Strimzi instead of being copied by hand.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>